Income Statements of International Financial Reporting Standards Term Paper

Income Statements of International Financial Reporting Standards - Term Paper Example In addition, the US GAAP treatment allows either single step or multiple steps format for income statement captions. According to Epstein (2011), under US GAAP, expenses such as cost of sales and administrative expenses have to be classed by function whereas in IFRS, expenses can be classed by function or nature. According to US GAAP treatment, classification of extraordinary items is permitted under certain circumstances and it can also be segregated within operating income. In contrast, IFRS bans classification of unusual items although it permits segregation of such items. Epstein (2011) states that the US GAAP considers estimated operating results of a discontinuing operation while measuring the expected gain or loss on disposal; on the other hand, IFRS reports actual operating results of a discontinuing operation as incurred. US GAAP provides a broader definition for discontinued operations while IFRS sets a narrow definition. Under US GAAP, restructuring costs are recognized on ly when it becomes necessary but IFRS recognizes restructuring costs when it is announced. Finally, additional comprehensive income items may be presented in changes in stockholders’ equity statement under US GAAP; but, this practice is not permitted under IFRS treatment. Differences in Balance Sheets As in the case of income statement, the IFRS balance sheet is also dissimilar to a typical US GAAP balance sheet. In the opinion of Epstein (2011), limited guidance on offsetting of assets and liabilities is a characteristic feature of US GAAP; however, IFRS insists specific guidance on offsetting of assets and liabilities. In case of IFRS, financial position’s classified statement is essential unless liquidity ordering is more meaningful. In contrast, such a statement is not required under US GAAP. Differences also exist in the definition of current/noncurrent between IFRS and US GAAP. The US GAAP treatment does not allow offsetting of assets and liabilities with various counterparties but it allows offsetting with same counterparties if and only the intention is to settle â€Å"net† (Epstein, 2011). On the other hand, IFRS permits some offsetting of assets and liabilities with various counter parties if legal provision allows it. Exclusion of long-term debt from current liabilities is a specific feature of IFRS. The US GAAP treatment refinances the exclusion of long term debt. The IFRS treatment states the minority interests as a component of equity while US GAAP guidelines restrict the presentation of minority interests as equity. As per the structure of US GAAP balance sheet format, entries are presented as total assets balancing to total liabilities in addition with shareholders’ equity. In contrast, IFRS entries include current and non-current assets and current and non-current liabilities. While US GAAP presents items on the basis of decreasing order of liquidity, the IFRS presents the items in the increasing order. Advantages o f IFRS to End Users Generally company management, shareholders, investors, and third parties such as banks and other financial institutions are the end users of financial statements. They get ranges of advantages if companies use IFRS accounting in financial statements. To the extent that financial statement information is not available form external sources, investors and other external users give emphasis on company financial statements.

Ethics and Law in Business and Society Research Paper

Ethics and Law in Business and Society - Research Paper Example Significant analysis and evaluation of the policies have been conducted to determine the effectiveness of these policies. Lastly, the study will provide some recommendation plans in order to overcome the possible issues and challenges. History of the Act It is important for the government, authorized bodies and employers to take care of the needs of the employees in an organization as employees are considered as one of the major assets of an organization. Significant work performance of the skilled and effective employees helps the business organization to achieve significant growth rate. In addition to this, effective business performs ace of the business units ensures economic growth of a nation. This specific act or program was required in order to cover and support the basic rights of the employees in an organization. This Federal Employees’ compensation act was developed in the year 1916 to ensure social welfare. This act was developed in order o support those employees w ho are physically or mentally unable to justify job responsibility. The major objective behind the development for the acts and programs was basically for a good social cause. It was highly important for the employees who are disabled, retired or physically challenged to get the benefits from the employers or from the federal government or from the authorized bodies to look after himself and his family. These funds can be provided to all the employees who are affected due to the workplace-related issues. In addition to this, several Federal Employees’ Compensation Act programs were started to organize by the federal government in order to improve the scenario of the society. According to this act, an individual can get different benefits based on the eligibility. The elements of the Federal Employees’ Compensation Act program include several aspects. According to this act, each and every mentally or physically affected employee in a workplace can get significant compen sation or service benefits (Ullmann, 2003). It is important for an organization to ensure healthy and safe workplace environment. The federal government of United States of America supported this act and act related programs to ensure the security of each and every disabled employee. Several types of benefit policies are proposed and developed in order to improve the lifestyle of these types of federal employees. However, the policymakers failed to develop the policy measures that created several conflicts and issues in later part. Several differentiated policies were developed and implemented under this Federal Employees’ Compensation Act in the year 1974 due to rising problems and issues in the states. however, the federal government of United States of America and other policymakers somehow failed to fulfill its overall objective due to lack of effective policy measures and i9nadequate development of eligibility criteria.

The U.S. Criminal Justice System Essay Example | Topics and Well Written Essays - 750 words

The U.S. Criminal Justice System - Essay Example The U.S criminal justice system has evolved as an assortment of various structures and components which operate independently. Like the systems in other countries, the U.S criminal justice is an interaction of three major components; the law enforcement agencies, the court systems and the correctional system (Carlson and Garrett, 2006). Each of the systems operates as an independent entity with little association among the various agencies. The American system majorly owes its roots from the England during the colonization era. During the colonial era, issues of crime were majorly handled by vigilante groups and private citizens. In absence of a governing system with regard to administration of justice, the British colonialists introduced several English legal traditions in America without replacing the private system and the customs adapted from other parts of the world. However, this informal system became obsolete due to the increasing population and urban growth paving way for el ites under the premise of enlightenment to challenge the existing criminal justice system which was primarily based on capital punishment and torture among other inhumane acts. In the wake of the enlightenment era, there was a move towards a more defined system with written rules and punishment. The central dogma for the justice system advocated by the enlightenment group was the need to have a system which would make people more aware of illegal actions and their respective consequences.   There was also need for equality and uniformity to be applied in the administration of justice. The American Revolution set the stage for the U.S to establish its own criminal justice system free from interference by the British. A rapid transformation of the criminal justice system was witnessed in the nineteenth century marked by increase in urban law enforcers and correctional system. However, the increased level of crime despite the transformations paved way for professionalism in the crimi nal justice system in an effort to understand the root causes of crime and effective control measures (Matthews et al, 2007). The increased professionalism led to implementation of more effective policies and processes in the justice system. This led to heightened efforts in empowering the various law enforcement agencies, courts and correctional systems at federal, state and county levels. As a result, the U.S system has remained as a complex assortment of highly fragmented organizations which interact with each other indifferent ways. Though there have been calls for transformation of the U.S criminal justice towards a unified system, such efforts have been met with opposition from various stakeholders like politicians and other beneficiaries hence majority of the states have retained the fragmented system.

Avocado Leaf Plasticity Essay Example for Free

Avocado Leaf Plasticity Essay INTRODUCTION: Phenotypic plasticity, or differing phenotypes from one genotype in different environmental conditions, is a way for sessile organisms to adapt to changing environmental conditions (Valladares et al., 2007). Plasticity was expected to be abundant, however, it did not occur as often in nature due to resource limitations and environmental stress (Valladares et al., 2007). An experiment by Matos tested the phenotypic plasticity to light availability in shade and sun leaves of coffee trees (Matos et al. , 2009). Their research indicated that compared [to] sun leaves, shade leaves had a lower stomatal density, a thinner palisade mesophyll, a higher specific leaf area, and improved light capture†¦ (Matos et al., 2009). The sun leaves were described as generally thicker with an enhanced quantity of palisade mesophyll (Matos et al., 2009). Our objective was the presence of phenotypic plasticity in avocado trees based on the differences in the morphology of shade and sun leaves. In our study, we asked whether there is a difference in surface area, length-to-width ratio, mass, specific leaf mass, and color between shade leaves and sun leaves in avocado trees. We hypothesized that there would be no significant differences in surface area, length-to-width ratio, mass, specific leaf mass, and color between shade leaves and sun leaves. METHODS: We collected our seventy samples of avocado tree (Persea americana) leaves, in equal amounts of sun and shade leaves, at an avocado tree grove located north of Building 3 and University Drive at Cal Poly Pomona on Thursday, October 24, 2013 at 9:00 am. They were randomly and interspersedly collected throughout the grove. We split the grove into five areas, split into five teams of two, and was assigned to one of the five areas. Each team picked a number for the trees in their region and a random number was selected from a random number table to select a tree corresponding to that number. A random number table was used to pick the corresponding quadrant, branch, and leaf.  This process was done twice on each tree in the understory for shade leaves, and in the canopy for sun leaves. Each leaf was measured for its surface area, length-to-width ratio, mass, specific leaf mass, and color. Surface area was measured by a leaf area meter in squared centimeters. Length-to-width ratio was measured by measuring the length (vertically along the bridge of the leaf) and the width (horizontally on the widest part of the leaf) with a ruler in centimeters, and dividing the length by the width. Mass was calculated by a balance in grams. Specific leaf mass (thickness) was measured by dividing the mass by its surface area in grams per squared centimeter. Color was measured by having three reference leaves provided by the instructor, indicating light (L), medium (M), and dark (D) leaves and compared our collected leaves. After recording all of the data, these data were then input into a statistical program called StatCat to determine normality through a normality test. The data for surface area, length-to-width ratio, mass, and specific leaf mass for sun and shade leaves were both normal, therefore, we chose a paired sample t-test for all of them. A normality test was not needed for color for sun and shade leaves due to it being a nominal scale data. The number of light, medium, and dark shade leaves were tallied up according to color, and the same was done for the sun leaves. A contingency table was made in Excel, and used in StatCat to test our hypothesis. The paired sample t-tests were also done through StatCat, which then gave us the appropriate results to test our hypotheses. RESULTS: Shade leaves had a significantly larger surface area than sun leaves (t = -3.7313, P = 0.00069; Table 1). Shade leaves had a significantly larger length-to-width ratio than sun leaves (t = -2.7162, P = 0.01031). Shade leaves had no significant difference in mass than sun leaves (t = -1.4871, P = 0.1462). Shade leaves had a significantly smaller specific leaf mass than sun leaves (t = 5.82093, P = 1.5Ãâ€"10-6). Shade leaves were significantly darker than sun leaves (X2 = 18.417, P = 0.0001).

Effective Community Participation Strategies Management Essay

Effective Community Participation Strategies Management Essay Introduction Community participation is the creation of opportunities to enable all members of a community to actively contribute to and influence the development process, while sharing equitably in the fruits of development (UN 1981). Midgley, Hall, Hardiman and Narine (1986) define community participation as the direct involvement of ordinary people in local affairs. Community participation can be summed up as a means of educating citizens in order to increase their competence. Reid (2000) defines community participation as a vehicle for influencing decisions that affect lives of citizens and an avenue for transferring political power. However, it can also be a mechanism for ensuring accountability, receptivity and sensitivity of social services to local communities. Successful community participation allows community members to act in response to public concerns, empowers community members to openly give their views about decisions that affect them and to actively take responsibility for chang es in their community. Importance of Community Participation According to WHO (2002), community participation helps communities to target resources more effectively and efficiently, allowing people to become more responsive to community needs and take responsibility. Communities have a wealth of untapped resources and energy that can be harnessed and mobilized through community participation. Community participation methods empower people to creatively develop skills and build competencies and capacities within communities. Furthermore, better and more sustainable decisions are made by involving communities in decision making because community participation is a way of extending the democratic process by opening up governance and redressing inequality in power. It offers new opportunities for creative thinking, innovative planning and development (WHO 2002). Heberlein (1976) notes that better community decisions are the ones that involve citizens at community level and they are generally more acceptable to local people. Cook (1975) argues that citizen participation in community affairs serves to check and balance political activities by allowing fuller access to benefits of a democratic society. This increases democracy and combats exclusion. WHO (2002) points out that community participation in decision making, planning and implantation is a human right. It is therefore important to implement new structures of governance that transcend citizens being viewed as passive recipients of services provided by agencies and decided by few representatives. This will open up genuine community participation at grassroots, empowerment of local communities and create a sense of citizenship. Community participation ensures ownership and sustainability of programs, provides a source of information, knowledge as well as experience and eliminates deficiencies in the society, empowering members to put emphasis on problem solving (Christensen and Robinson 1980). Cahn and Camper (1968) suggest that merely knowing that one can participate in community development and become accountable for development of a local community promotes dignity and self sufficiency within the individual. Interestingly, Cook (1975) points out that community participation can legitimise a program, its plans, actions and leadership, which brings the difference between success and failure of the program. Programs that lack community support end up failing while the ones embraced by the community become successful. WHO (2002) views community participation as an essential tool for ensuring that interventions and programs aimed at promoting health, wellbeing, quality of life and environmental protection are sustainable. Reid (2000) argues that active community participation is the key to building an empowered community. Participating communities are open to involvement by all groups and responsibilities are divided with an aim of engaging special talents and interests of contributing organizations and individuals thus decentralising power and responsibilities. Participating communities carry out their activities openly and publicise them widely. The citizens are well informed about community work as well as their opportunities for personal involvement in meaningful roles (Reid 2000 and Cook 1975). Successful community participation involves participating communities that do not discriminate against each other. Such communities willingly offer themselves to community involvement and perform their activities with an open mind. They are not controlled by any single organization, group or philosophy and their leadership is used to facilitate discussion of diversity of viewpoints instead of pushing for i ts own agenda. What Makes Effective Community Participation Community participation requires going beyond consulting to make citizens an integral part of decision making and action process. It should not be viewed as a response to initiatives or agendas from politicians and professionals (WHO 2002). Spiegal (1968) notes that citizen participation is the only process that can meaningfully tie community development programs to members of local communities. The participation programs involve a significant number of people in situations or actions that enhance their well being. It involves peopleà ¢Ã¢â€š ¬Ã¢â€ž ¢s income, their security, time, commitment, skills and even their self esteem. According to Brager, Specht and Torczyner (1987) there are three major aspects to be considered for successful community participation, namely: the kind of community participation under consideration, type or nature of people participating and how the participation takes place. Evans (1974) also points out the significance of issues such as, who participates, the nature of activities that people participate in, why they participate and how the activities they are participating in contribute to principles that they value as a community. Sharing community responsibilities, assuming good intentions for all stake holders involved in community initiatives and affirming the community strengths brings oneness to the community and creates effective community participation. According to WHO (2002), valuing partnership between local communities and sponsors of a community initiative and confirming benefits of the initiative is a vital tool for effective community participation. Local communities do not want to be treated as being helpless. Treating them with respect no matter how poor they are, listening to them and learning from them boosts their morale to participate and own the community initiatives (UNCHS 1986). Smithies and Webster (1998) argue that successful community participation must have support at community grassroots level, with full consultation and involvement of local communities in planning and implementation of such initiatives. Research has shown that community initiatives implemented through resourcing grassroots work and local action with both geographical communities and communities of interest as the starting point for community initiatives has yielded great success and proved effective and sustainable. This process has often led t o establishment of trust and mutual respect between communities and professionals intending to work with such communities to achieve desired objectives. WHO (2002) identifies networking for the purposes of facilitating development of community and professional infrastructure as an integral part of effective community participation. Networking gives an opportunity to communities, professionals and all those involved in community projects to share common experiences, strengthen competencies and build alliances that focus on recognition and realisation of potential people in organizations working to ensure effectiveness, capabilities and adaptability within the context of community participation. Effective community participation involves planning of concept, process, structure and content Smithies and Webster (1998). This ensures meaningful and long-term community participation at all stages of community projects. This requires an effective two way communication to ensure that the views of community members are incorporated into strategic plan. Spiegal (1968) observes that local communities should be given an opportunity and responsibility to manage their own resources, define their needs, aspirations and make decisions affecting their well being. An effective community participation program is therefore established on the basis that local people have the innate capacity to understand and act on their own problems. The approach of such initiatives should be people centered and consensus driven and involve vulnerable groups of such as people with disabilities and the elderly. They should also have a gender balance. Cahn and Camper (1968) argue that sustainable and inclusive community participation should aim at developing community infrastructures, whereby formal arrangements for communication, consultation, collaboration as well as informal networks for inter agency liaison should be developed with a shared understanding and a common purpose. All stakeholders should work in partnership to share skills and be committed to mutual learning and joint training as they appreciate and acknowledge resources that communities have in terms of expertise. Barriers to community involvement should be addressed by availing resources and taking positive approach towards building effective communication among all stake holders and adequate information management. There should be good governance and transparency in decision making to avoid prejudice. Barriers to Effective Community Participation USAID (2000) notes that community initiatives are highly likely to fail in societies where there is unfair distribution of benefits of community participation or community work among local members. Highly individualistic societies where there is little or no sense of community partnership are faced with lack of cooperation, selfishness, corruption and at times mismanagement of resources that could benefit the entire community. Bass (1995) observes that community initiatives that lack policies, laws and institutions that encourage, support, manage and reward local participation in planning and development process are faced with challenges of failing. The success of any community participation initiative is largely dependent upon the precise strategy scope, goals and likely participants. Political and cultural circumstances dictate the extent in which community initiatives succeed. Community initiatives influence by bad governance and political interference never benefit the locals but are only used by politicians as political milestones. Mayo and Craig (1995) note that communities need an appropriate organisational structure put in place for them to express their interests and build effective community participation. People are reluctant to join community initiatives whose organisational structures are cumbersome, time consuming, dictatorial or grossly insufficient. Communities that have little knowledge or limited information on the nature and benefits of community initiatives withdraw their participation and often oppose the initiatives because they are hardly involved in their planning and decision making. Case Studies Case Study 1: Newcastle City Council Newcastle city council works through partnership with other organisations such as police, universities, health service providers, all groups and individuals from community, voluntary and private sectors to ensure that community initiatives influence the future prosperity of the city (Newcastle city council). The council has a variety of community participation initiatives that have been quite successful such as building schools for future, whose main vision is to raise aspirations, opportunities and achievements of all Newcastle residents and to create a culture of learning that enhances creativity and economic prosperity. Other Newcastle city council initiatives include the rough sleepers initiative and housing initiatives. The main objectives of Newcastle city council are: to develop and sustain opportunities for local people and groups for the purpose of influencing what goes on within their communities, to create opportunities aimed at shaping and influencing quality service delivery to local communities, to manage and coordinate engagement activities for consistency, quality and partner participation. The Newcastle city council aspires to ensure that community development activities provide opportunities for entire community to participate in community programs and share their skills (Newcastle city council). These objectives have been achieved through priorities such as successful coordination and leadership of participatory community initiatives, development of protocols, toolkits and performance management framework. The council has a web based resource for effective consultation as well as inclusive ward committee structures to establish views of all community groups, to improve coordination with partners in engagement activities and to enhance skills and expertise in community development participation (Newcastle city council). Each ward in Newcastle has a neighborhood response manager and a neighborhood response team to ensure that views of residents are incorporated in service delivery. Most of the decisions are made through effective consultation with local community groups, which are then involved in implementation of such decisions through active participation in service delivery (Newcastle city council). Newcastle city council has been a successful community initiative through active participation of local communities at grassroots, Case Study 2: The Tsunami Project Following the Tsunami disaster, several groups of grant makers such as the American Jewish society, Global fund for children, Global green grants fund, Oxfam America and Global fund for women among others positively responded to assist the affected communities. However, a closer look at available literature on Tsunami shows that the central role of local organisations such as mechanisms for ensuring local participation is widely recognised throughout the Tsunami community initiatives. However, it is evidently clear that grassroots participation in Tsunami response was insignificant, this forced local communities to compete for resources and recognition (Roper and Harvey 2006). The Tsunami initiatives seem to have been driven by what grant makers had planned and purposed to deliver instead of being driven by the needs of local communities involved. The initiatives were planned and implemented without consultations with local communities. This made it difficult for more sensitive issues emerging after the disaster to be addressed because beneficial roles could only be achieved through tapping into existing community groups, focusing on marginalised groups to strengthen their capabilities, building solidarity across social divides, funding women- led initiatives to promote gender equality and giving local people an opportunity in coordinating implementation of temporary shelter (Roper and Harvey, 2006). The objectives of Tsunami response by several organisations were not well defined to members of the local community, there was little involvement of local communities in planning and implementation of Tsunami initiatives and this made the local communities feel like they were left out of the projects, without a sense of ownership hence it was difficult to address the real problems facing communities after the Tsunami disaster. Conclusion This research paper started by defining and discussing community participation initiatives and what makes community participation initiatives to be successful. Community strategies and initiatives are only successful when the local communities are fully involved in planning and implementation of such initiatives. Participatory community initiatives bring psychological satisfaction to members of the local communities, giving them a sense of ownership to community initiatives while tapping into the unlimited potential of skills and knowledge from local communities. Through the two case studies discussed, Newcastle city council has been a successful community initiative because local communities are actively involved in planning and implementation of community initiatives. This gives them a sense of ownership and the ability to identify with the initiatives and contribute to the total well being of the entire community through participation. They are not afraid of offering their expertise because they know the benefits of being involved in community initiatives. On the other hand, local communities were not given a chance to participate in planning and implementation of Tsunami project. The implementing agencies viewed communities as desperate people and did not give them an opportunity to air their views or become involved in planning and implementation of the project. This led to unfruitful results in implementation of the community initiative, with massive failure of the projects and even increased risks to local communities after implementat ion of the projects. Community participation is not an idle principle. Communities that have chosen to follow it find that not only do they derive more satisfaction from the joy that comes from open community involvement, but they also achieve more results, more rapidly and with greater benefit to the community as a whole. In short, participating communities succeed better than those that only pay lip service to this important principle.

In Distrust of Movements :: Analysis, Wendell Berry

Humans crave improvement, humans crave progress, and humans crave identity. For many, these cravings are satisfied within the ideas and actions behind social movements. According to Dictionary.com, the definition of a social movement is, â€Å"a group of people with common ideology who try together to achieve certain general goals† (n.d.). Frequently, these social movements center around a singular issue. In his essay titled â€Å"In Distrust of Movements,† Wendell Berry (2000) refers to single-issue movements as â€Å"hopeless† (p.333). He writes, â€Å"I have had†¦ a number of useful conversations about the necessity of getting out of movements – even movements that have seemed necessary and dear to us – when they have lapsed into self righteousness†¦ as movements seem almost invariably to do† (p.331). Berry is incorrect in his belief that single-issue movements are ineffective and inevitably fail, and flagrantly disregards history in making such an assertion. Since the advent of the printing press, human communication has grown exponentially. The 20th century is certainly no exception to this trend as we have seen in the advent of radio, television, and the internet. The ease of communication allowed the voice of the masses to be readily heard, and has proved advantageous for social activists and the causes they championed. Such advantages did not go to waste as we have witnessed in movements like the civil rights movement or Fair Trade. Even today, we hear the cries of the â€Å"Occupy Wall Street† protestors. The truth is, progressive movements and their political pull are here to stay and contrary to Berry’s (2000) belief, those that grow around a â€Å"single issue† are just as successful as their multi-faceted counterparts. To give an example, the aforementioned Civil Rights Movement stands as a prominent specimen of a triumphant single-issue cause. Clear and precise, the goal of this cause was to grant African Americans the same legal rights allowed to any other American citizen. This effort ultimately led to such legislation as the American Civil Rights Act of 1964 (â€Å"The Civil Rights Movement,† n.d.), and the Fair Housing Act of 1968 (â€Å"Fair Housing Laws,† n.d.). Berry (2000) asserts that one of the major faults in movements is that â€Å"They almost always fail to be radical enough, dealing finally in effects rather than causes† (p.331). What was the Civil Rights Movement though, but a solution to an â€Å"effect† rather than a cause?

Thermodynamic Analysis and Performance Characteristics

AEROSPACE ENGINEERING SCHOOL OF MECHANICAL ENGINEERING AND DESIGN THE THERMODYNAMIC ANALYSIS AND PERFORMANCE CHARACTRISTICS OF A TURBOFAN JET ENGINE By J. E, Ibok 2011 Supervisor: Dr Lionel Ganippa ABSTRACT This work focuses on the performance analysis of a twin spool mixed flow turbofan engine. The main objective was to investigate the effects of using hydrogen, kerosene and natural gas fuel on the performance characteristics such as net thrust, specific fuel consumption and propulsive efficiency of the turbofan.Another aim of this work was to introduce the concept of exergy and thermoeconomics analysis for twin spool mixed flow turbofan engine and show the components that contributes the most to the inefficiency of the engine. A generic simulation was carried out using Gas Turb 11 software to obtain reasonable analysis results that were verified with a real-time JT8D-15A turbofan engine. The parametric analysis was done for constant value of mass flow rate of fuel and constant turb ine inlet temperature for all three fuels.The result were rightfully obtained for these analysis cases and discussed accordingly. Brunel University Mechanical Engineering Academic Session: 2010/2011 Name of Student: Johnson Essien Ibok Supervisor:Dr Lionel Ganippa Title: The Performance Characteristics and Thermodynamics Exergy and Thermoeconomics analysis of a Twin Spool Mixed Flow Turbofan Engine Operating at 30,000ft at M0 0. using Kerosene, natural Gas and Hydrogen Fuel. Abstract: This work focuses on the performance analysis of a twin spool mixed flow turbofan engine. A generic simulation was carried out using Gas Turb 11 software to obtain reasonable analysis results that were verified with a real-time JT8D-15A turbofan engine. The parametric analysis was done for constant value of mass flow rate of fuel and constant turbine inlet temperature for all three fuels.The result were rightfully obtained for these analysis cases and discussed accordingly. Objectives: The main aim of this work is to conduct the parametric cycle simulation of a twin spool mixed flow turbofan engine and investigate the performance characteristics of it. Another aim of this work is to show the effects of using hydrogen, Kerosene and natural gas fuel on the overall performance of the twin spool mixed flow turbofan engine.Also, the purpose of this work is to introduce the use of the second law of thermodynamics analysis known as exergy and thermoeconomics in analysis the twin spool mixed flow turbofan engine Background/Applications: This work is applicable in so many ways when it comes to the overall performance optimization and feasibility analysis of a jet engine. This work relates to the aerospace and aviation industries since the turbofan engine is amongst the vast number of jet engine used in propulsion of aircrafts.There is increasing pressure in the aviation industry to reduce pollution and depletion of energy resources while at the same time maintaining reasonable investment cost and high overall performance. Hence, this research was conducted in hopes of coming up with a new solution to this problem. Conclusions: The main conclusion drawn from the performance analysis is that hydrogen fuel produced the highest thrust level and the lowest specific fuel consumption between the three fuels for a constant mass flow rate of fuel.Kerosene fuel generated thrust level can be increased if it is mixed with a small amount of hydrogen. The Exit jet velocity ratio remained constant despite the increasing bypass ratio for all three fuels at constant mass flow rate of fuel. Using the exergetic analysis showed that the combustion chamber and the mixer contributed the most to the inefficiency of the turbofan engine. The amount of exergy transferred into the turbofan engine by hydrogen was depleted in the smallest ratio compared to natural gas and kerosene for constant mass flow rate of fuel.The thermoeconomics analysis showed that it is preferable to use local based co st evaluation to quantity specific thermoeconomics cost of thrust than the global method since the value was lower. Results: The results obtained from the simulation using Gas Turb 11 produced an error range of 0. 25% – 8. 5% when verified with the actual test data of the JT8D-15A turbofan engine. The results obtained for the analysis defined a reference design point at which the parametric analysis was conducted on. The analysis was done in three cases as shown clearly in the test matrix in table 1 below.Analysis| Parameters being varied| Parameters Kept Constant| Performance Characteristics| case 1| * Bypass ratio * Turbine Inlet temperature| * HPC Pressure Ratio * LPC Pressure Ratio * Fan Pressure Ratio| * Velocity ratio * Fuel-Air-ratio * Turbine inlet temperature * Net thrust * Specific Fuel Consumption * Thermal efficiency * Propulsive efficiency| case 2| * Bypass Ratio * Three different fuelsmH2mCH4mC12H23| * Mass flow rate of fuel * HPC Pressure Ratio * LPC Pressure R atio * Fan Pressure Ratio| | Case 3| * Bypass Ratio * Three different fuelsmH2mCH4mC12H23| * Turbine inlet temperature * HPC Pressure Ratio * LPC Pressure Ratio * Fan Pressure Ratio| | Table 1 The Test matrix of the Parametric Analysis. The exergy analysis was done for the parametric analysis of case 2 and case 3 where the exergy destruction rates, exergetic efficiency, exergy improvement potential rate and fuel depletion ratio were calculated. The distribution of these results throughout each component of the turbofan engine was represented with bar charts and Grassmann diagram. The thermoeconomics analysis was conducted for analysis case 2 using kerosene fuel.The specific thermoeconomics cost of thrust was calculated using global and local based cost evaluation methods. ACKNOWLEDGEMENTS First of all, I would like to thank my parents for their financial support and encouragement because without them I would not be here and be able to do this work. I am deeply thankful to my supervi sor, Dr Lionel Ganippa for believing in me and giving me the opportunity to work with him in this field of study. I am also thankful to him for giving the necessary guidance and advice and his enthusiasm and innovative ideas inspired me. Finally, I would like to thank Mr Joachim Kurzke for providing me with the necessary software needed for my dissertation. Table of ContentsAcknowledgements i Contents ii List of Notations and Subscripts iv List of Tables vi List of Figures vi Chapter 1: Introduction1 1. 1. Aims and Objectives2 1. 2. Computational Modeling3 Chapter 2: Jet Engines4 2. 1. Performance characteristics4 2. 1. 1. Thrust4 2. 1. 2. Thermal Efficiency5 2. 1. 3. Propulsive efficiency5 2. 1. 4. Overall efficiency6 2. 1. 5. Specific Fuel Consumption6 2. 2. Fuel and Propellants For Jet Engines7 Chapter 3: Turbofan Jet Engines †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ †¦8 3. 1. Introduction 8 3. 2. Classification of Turbofan Engines9 3. 3. Major Components of a Turbofan Engine10 3. 3. 1. Diffuser10 3. 3. 2. Fan and Compressor11 3. 3. 3. Combustion Chamber12 3. 3. 4. Turbine13 3. 3. 5. Exhaust Nozzle14 3. 4.Thermodynamic Process and Cycle of a Twin Spool Mixed Flow Turbofan Engine15 Chapter 4: Mathematical and Gas turb 11 Modeling of the turbofan Engine18 4. 1. Station Numbering and Assumptions18 4. 2. Design Point Cycle Simulation of the Turbofan Engine18 4. 3. Off-design Point Cycle Simulation of the Turbofan Engine21 4. 3. 1. Module/Component Matching 22 4. 3. 2. Off-Design Point Component Modeling22 Chapter 5: Methodology, Results and Discussions26 5. 1. General Relationship equations of the Major Parameters27 5. 2. Results and Discussions of Parametric cycle Analysis of Case 129 5. 3. Results and Discussions of Parametric Cycle Analysis of Case 235 5. 4.Results and Discussions of Parametric Cycle Analysis of Case 343 Chap ter 6: Exergy and Thermoeconomics Analysis of the Turbofan Engine49 6. 1. Exergy Analysis49 6. 1. 1. Exergy Analysis Modeling 50 6. 1. 2. Exergy and Energy Balance Equations of the Components58 6. 1. 3. General Relationships in Exergetic Analysis of the Turbofan Engine60 6. 1. 4. Results and Discussions61 6. 1. 5. Grassmann Diagram72 6. 2. Thermoeconomics Analysis74 6. 2. 1. Thermoeconomics Analysis Modelling74 6. 2. 2. Global Based Cost Evaluation76 6. 2. 3. Local Based Cost Evaluation77 6. 2. 4. Results and Discussion of the Thermoeconomics Analysis78 Chapter 7 Conclusions and Future Work80 Reference Appendix A Exergy Analysis Results Appendix B Thermoeconomics Analysis resultsList of Notations and Units ?| Isentropic efficiency| ?| Total Pressure ratio| m| Mass Flow Rate (kg/s)| f| Fuel/Air Ratio| M| Mach Number| Pt| Total pressure (kPa)| Tt| Total Temperature (K)| NCV| Net Calorific Value (MJ/kg)| Ht| Total Enthalpy (kJ/kg)| V| Velocity (m/s)| ?| Bypass Ratio| T| Static Temperat ure (K)| P| Static Pressure (kPa)| N| Actual Spool Speed (RPM)| Nc| Corrected Spool Speed (RPM)| mc| Corrected Mass Flow Rate (kg/s)| R| Universal Gas Constant (kJ/kmolK)| ?0| Standard Chemical Exergy (kJ/kmol)| Ex| Exergy Rate (MW)| xi| Mole Fraction| cp| Specific Heat at Constant Pressure (kJ/kgK)| ?| Ratio of Chemical Exergy to NCV| ?| Exergetic Efficiency| | Fuel Depletion Ratio| W| Power Rate of Work done (MW)| List of Subscripts| | LPT| Low Pressure Turbine| HPT| High Pressure Turbine| CC| Combustion Chamber| HPC| High Pressure Compressor| LPC| Low Pressure Compressor| d| Diffuser| noz| Nozzle| mix| Mixer| dest| Destruction Rate| 0, ambFAR| Ambient conditionFuel-Air-Ratio| CH| Chemical| PH| Physical| KN| Kinetic| PN| Potential| IP| Exergy Improvement Potential Rate (MW)| CRF| Cost Recovery Factor| c| Specific Thermoeconomic Cost (MJ/kg)| STD| Standard Temperature and Pressure| TIT| Turbine Inlet Temperature| TSFC| Thrust Specific Fuel Consumption (g/kNs)| SFC| Specific Fuel Co nsumption| p| Propulsive| TH| Thermal|O| Overall| T| Thrust| equip| Equipment| PEC| Capital Cost of Equipment| List of Tables Table 1 input parameters for Design Point Cycle Simulation on Gas Turb 1119 Table 2 Comparison table for the Actual Test Data and Simulated Data using gas Turb 1121 Table 3 Comparison Table for Actual Test Data and Simulated Off-Design Point data Using gas Turb 11. 25 Table 4 Equivalence Ratio of the three Fuels Combustion Processes†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 62 Table 5 Assumed Capital costs of Each Component of the Turbofan Engine. 75 Table 6 Flow of Specific Thermoeconomics Cost in all the Components 79 List of Figures Figure 1 Classification of Turbofan Engine9Figure 2 Layout of Forward Fan Twin Spool Mixed Flow Turbofan16 Figure 3 T-S Diagram for the Forward Fan Twin Spool Mixed Flow Turbofan17 Figure 4 Design Point Cycle Simulation Algorithm Using Gas Turb 1120 Figure 5 Example of a Compressor Performance Map/Cu rve24 Figure 6 Effects of Varying Bypass Ratio at Constant Values of TIT on Fuel-Air-Ratio30 Figure 7 Effects of Varying Bypass Ratio at Constant Values of TIT on Exit Velocity Ratio30 Figure 8 Effects of Varying Bypass Ratio at Constant Values of TIT on LPT Exit Pressure Ratio31 Figure 9 Effects of Varying Bypass Ratio at Constant Values of TIT on Net Thrust32 Figure 10 Effects of Varying Bypass Ratio at Constant Values of TIT on Specific Fuel Consumption33 Figure 11 Effects of Varying Bypass Ratio at Constant Values of TIT on Propulsive Efficiency34 Figure 12 Effects of Varying Bypass Ratio t Constant Values of TIT on Thermal Efficiency35 Figure 13 T-S diagram of using Hydrogen Fuel when the bypass Ratio is increased36 Figure 14 Variation of Fuel-Air-Ratio with Bypass Ratio at Constant Fuel Flow Rate using three different Fuels37 Figure 15 Variation of TIT with Bypass Ratio at Constant Fuel Flow Rate using three different Fuels37 Figure 16 Variation of Exit Velocity Ratio with Byp ass Ratio at Constant Fuel Flow Rate using three different Fuels38 Figure 17 Variation of LPT Exit Pressure Ratio with Bypass Ratio at Constant Fuel Flow Rate using three different Fuels39 Figure 18 Variation of Net Thrust with Bypass Ratio at Constant Fuel Flow Rate using three different Fuels40 Figure 19 Variation of Specific Fuel Consumption with Bypass Ratio at Constant Fuel Flow Rate using three different Fuels41 Figure 20 Variation of Thermal Efficiency with Bypass Ratio at Constant Fuel Flow Rate using three different Fuels42 Figure 21 Variation of Propulsive Efficiency with Bypass Ratio at Constant Fuel Flow Rate using three different Fuels43 Figure 22 Variation of Fuel-Air-Ratio with Bypass Ratio at Constant TIT using the three Different Fuels44 Figure 23 Variation of Exit Velocity Ratio with Bypass Ratio at Constant TIT using the three Different Fuels44 Figure 24 Variation of LPT Exit Pressure Ratio with Bypass Ratio at Constant TIT using the three Different Fuels45 Figure 25 Variation of Net Thrust with Bypass Ratio at Constant TIT using the three Different Fuels46 Figure 26 Variation of Specific Fuel Consumption with Bypass Ratio at Constant TIT using the three Different Fuels46 Figure 27 Variation of Propulsive Efficiency with Bypass Ratio at Constant TIT using the three Different Fuels47 Figure 28 Variation of Thermal Efficiency with Bypass Ratio at Constant TIT using the three Different Fuels48 Figure 29 Variation of Exergy Destruction Rate Using the three Fuels for Analysis Case 262 Figure 30 Variation of Exergy Destruction Rate Using the three Fuels for Analysis Case 364 Figure 31 Variation of Exergetic Efficiencies Using the three Fuels for Analysis Case 266 Figure 32 Variation of Exergetic Efficiencies Using the three Fuels for Analysis Case 367 Figure 33 Distribution of Exergy Improvement potential Rate Using the three Fuels for Analysis Case 268 Figure 34 Distribution of Exergy Improvement potential Rate Using the three Fuels for Analysis Case 369 Figure 35 variation of Fuel Depletion ratio using the Three Fuels for Analysis Case 270 Figure 36 variation of Fuel Depletion ratio using the Three Fuels for Analysis Case 371 Figure 37 Grassmann Diagram for the Exergetic analysis of Case 2 using kerosene Fuel for the Turbofan engine. 72 Chapter 1 Introduction Jet engines are complex thermodynamic systems that use a series of non-linear equation to define their thermodynamic processes and they operate under the principle of Brayton cycle.Brayton cycle is a cycle that comprises of the compressor, combustor and turbine working as a unit. Additionally, the major parameters that dictate the operational conditions of the engine at any point during the process are the relative altitude and Mach number. Mach number is the ratio of the velocity of the jet engine to the speed of sound. Basically, the main purpose of this type of thermodynamic system in aerospace industry is to accelerate a jet of air and as a result, generate enough thrust needed for flight. In addition, the design of jet engines is dependent of what purpose it will be used for in order to derive its maximum performance.For instance, in military application, jet engines are required to generate maximum thrust in minimum response time which consumes a lot of fuel whereas commercial jet engines are required to less noise generative, less fuel consuming and at the same time have high overall efficiency (El-sayed, 2008). There are certain factors that jet engine manufacturers take into consideration when designing jet engines which are the operating cost, engine noise, environmental emissions, fuel burn and overall efficiency. Accordingly, this has caused a global market competition for engine manufacturers like Rolls Royce, Pratt and Whitney, General Electric and CFM on who can produce the most efficient jet engines.In fact, Pratt and Whitney Company is working on a geared turbofan jet engine that they believe will reduce fuel burn, produce lesse r noise and emit less toxics while General Electric is coming up with simpler â€Å"ecore† jet engines that will be more fuel efficient than the current jet engines with as much as almost two fifths of current jet engines (Cassidy, 2008). Taking all that has been said into consideration, it can easily be asserted that by reducing the fuel consumption of the jet engine, the total temperature at the turbine blades will reduce thereby increasing the operating life and overall efficiency of the engine. Also, the total cost of the engine can be cut down. Indeed, Dr Pallan cited in (Ward, 2007) stated that reducing the fuel consumption by as little as 1% is highly longed after by engine manufacturers and this can result in very significant increase in the overall performance.In a general point of view, it can be said that the maximum point of achievement for jet engine manufacturers would be to design an engine that consumes the minimum amount of work in the compressor unit while g enerating the maximum amount of work in the turbine unit at minimum fuel supply. The main purpose of this work is to analyse the thermodynamic processes and performance of a jet engine using a simulation tool, exergy and thermoeconomics concept. 1. 1. Aims and Objectives The main objective of this work is to carry out the thermodynamic analysis and show the performance characteristics of a turbofan jet engine. In this work, the vivid explanation of the thermodynamics processes and cycle of each component of the turbofan engine starting from the diffuser to the nozzle will be covered. Also, the first and second law of thermodynamics with other laws will be applied extensively throughout this work.However, in the aspect of performance characteristics of the turbofan engine, a generic simulation will be carried out on a twin spool mixed flow turbofan engine. To relate this work to real life application, a JT8D-15A turbofan engine manufactured by Pratt and Whitney Company will be used a s the twin spool mixed flow turbofan for the simulation using the original design data. Indeed, the simulation tool that will be used is GasTurb 11 which was designed by Joachim Kurke and for more details on how it works can be found in (Kurke, 2007). This work will use the reference design point of the twin spool mixed flow turbofan at sea level with maximum take-off thrust to obtain the operating point of 30,000ft at M0 0. using the off-design performance simulation which will serve as the operating design point for the analysis in this work since the engine will spend most of its time in the cruise phase between 30000ft to 38000ft. The purpose of carrying this generic simulation of the turbofan engine is to investigate the effects of varying bypass ratio and turbine inlet temperature (thermal limit parameter) on the performance characteristics of the turbofan engine. In other words, the parametric cycle studies of the turbofan engine. This investigation will be done for three dif ferent cases which case 1 will be studying the effects of varying bypass ratio and turbine inlet temperature on the performance characteristics of the turbofan engine when some of the design choices are kept constant.The second case of study will be the comparison of the performance characteristics of the turbofan engine when three different fuels (kerosene, natural gas and Hydrogen) are used at the same mass flow rate using the same design point in case 1. Finally, the third case of study will be the comparison of the performance characteristics of the turbofan engine when the three fuels are undergoing the same combustion process that is constant turbine inlet temperature for the design point in case 1. This aspect of this analysis is very important owing to the growing problem of greenhouse effect and depletion of energy resources. In fact, statistics by the intergovernmental panel shows that aerospace industry is amongst one of the fast growing sources of greenhouse effect and t hat the emission of carbon dioxide will increase to five times what it is presently which is 3% (Symonds, 2005).Based on this, using alternative fuels like hydrogen and natural gas can tend to reduce pollution and consumption of energy resources risk and this work aims to show how that can be achieved while the overall efficiency of the engine is still high. Another approach of analysis in this work will be the use of the second law of thermodynamics analysis also known as exergy and thermoeconomics. This aspect of analysis of the turbofan engine will be done for the parametric analysis of case 2 and case 3 in efforts to also compare the three fuels that are being considered and show which fuel will cause the turbofan engine components to be most inefficient or have the most irreversibility.This analysis will be done by calculating the exergy relationships such as exergy transfer rates, exergy destruction rates, exergetic efficiencies, exergy improvement potential rates, and fuel de pletion ratios. Furthermore, the exergy analysis will be represented in a Grassmann diagram for parametric analysis case 2 of study. However, as for the thermoeconomics analysis of the turbofan engine, only parametric analysis case 3 studies will be done for only kerosene fuel and this work will aim to show how to use concept of local and global evaluation of thermoeconomic cost. 1. 2. Computational Modelling It will be very expensive and time wasting to design and develop new aircraft engine whenever an optimization or analysis wants to be done.In fact, Caoa Y, Jin, Meng and Fletcher (2005) stated that new ways should be developed to reduce aircraft engine design, maintenance and manufacturing cost in order to have effective worldwide market competition. Surprisingly, computer modelling is one approach of reducing manufacturing cost and time wasting. Computational modelling can simply be defined as the use of computer codes to replicate a typical system using some of its original d ata in order to analyse the system at varying conditions. The other side of the medallion shows simulation. There are many types of simulation tools normally used in simulating gas turbines such as Matlab/simulink, Modelica, Gas Turb 11, NPSS and many more. However, the simulation tool that will be adopted for the purpose of this dissertation is Gas Turb 11 designed by Joachim Kurzke.Gas Turb 11 is a language oriented program with a command prompt that calculates the output data without using block diagrams or graphical interface. It is user friendly in a sense that it is easy to find the tools library and to substitute data in for simulation. The Gas Turb 11 is specifically designed for simulation of all kinds of gas turbines starting from power generators to jet engines. Gas Turb 11 usually carries out two types of analysis which are the on design cycle point simulation and off-design cycle point simulation. Engine design point cycle simulation involves the study of comparing gas turbines of different geometry. This cycle design point must be defined before any other simulation can be done.On the other hand, off-design performance cycle point simulation involves the study of the behaviour of a gas turbine with known geometry. This cycle outlines the performance characteristics of each component such as performance maps, Overall efficiency. The type of simulation that will be done in this dissertation will involve the off-design and design point cycle. Chapter 2 Jet Engines 2. 1. Performance Parameter of Jet Engines 2. 2. 1. Thrust Thrust is the way of quantifying the ability of a jet engine to effectively utilise the energy added to it in order to propel or push itself forward in the opposite direction of the exiting jet in the exhaust nozzle.In other words, it is the reactive force to the force imparted by the exiting jet in the nozzle in accordance to Isaac Newton’s third law of motion. It is the most important parameter that has to be obtained for any jet engine and it depends heavily on the ingested mass of air, exiting velocity and pressure, the area of the nozzle, the flight velocity and ambient conditions. In fact, the mathematical expression for thrust which incorporates these factors is shown below as. Thrust=meVe-m0V0+Pe-P0Ae Where, e=the exit conditions at the exhaust nozzle, 0=ambient conditions at the inlet me=m0+mfuel Momentum Thrust=meVe; This is the thrust obtained from the reaction of the hot exhaust gases high velocity.Momentum Drag= m0V0 ; This the friction or drag force caused by the high velocity ingestion of air mass at the inlet. Pressure Thrust=Pe-P0Ae; This force is generated as a result of the higher exit static pressure compared to the ambient pressure which pushes back at the engine. Gross Thrust=meVe+Pe-P0Ae; It is the maximum obtainable positive thrust a jet engine can have when the drag forces are ignored. Special Cases of Thrust Take-off Thrust It is the thrust a jet engine can generate with its o wn power at static or low power setting which means the momentum drag component of thrust is ignored and the power of the engine at this point is equivalent to zero.This can be used to explain why the thrust of an engine at take-off condition is usually higher than at cruise condition since there is no momentum drag and effects of varying ambient condition. This only applies to turbojet, turbofan, and turboprop jet engines but when it comes to ramjet and scramjet, the air flow has to be accelerated by a booster system before it can start producing a positive take-off thrust. Pressure Thrust Component This is the thrust generated as a result of the static pressures of the exiting jet and ambient environment. In ideal cases where the nozzle has perfectly expanded the jet exit pressure to that of the ambient condition, the pressure thrust component will disappear which this case is not possible in reality.However, if the nozzle is choked which indicates that the ambient pressure is low er than the exit pressure of the jet, the pressure thrust component will have a positive effect on the net thrust. Also, if the nozzle tends to over expand the jet because of low energy addition to the jet and the exit pressure is lower than the ambient pressure, the pressure thrust component will have a negative effect on net thrust. 2. 2. 2. Thermal efficiency It is simply the measure at which energy in the engine system is converted. In other words, it is the measure at which total energy supplied to the engine system as heat transfer is converted to kinetic energy.In another way, it can easily be said to be the ratio of the power generated in the engine airflow to the rate at which energy is supplied in the fuel. ?TH=Power Generated in the Engine AirflowRate of Energy Supplied in the Fuel =12? meVe2-12? m0V02mfuel? NCV 2. 2. 3. Propulsive efficiency It is a measure at which kinetic energy possessed by air as it passes through the engine is converted into power of the propulsion of the engine. In mathematical terms, it is simply known as the ratio of thrust power to the power generated in the engine airflow. ?p=Thrust PowerPower Generated in the Engine Airflow = T? V012? meVe2-12? m0V02 2. 2. 4. Overall EfficiencyAs the name overall depicts, it is the resultant efficiency of a jet engine can have which is simply the product of the thermal and propulsive efficiencies. In mathematical terms, it is represented as shown below. ?O=? TH p =12? meVe2-12? m0V02mfuel? NCV? T? V012? meVe2-12? m0V02 =T? V0mfuel? NCV 2. 2. 5. Specific Fuel Consumption Specific fuel consumption as any other performance characteristics is a ratio and surprisingly it has a major effect on the economics of the aircraft as it is used to determine the aircrafts flight ticket costs. Specific fuel consumption has different expressions depending on what type of jet engine it is. For instance, in ramjet, turbojet and turbofan jet engines, it is the measure of the fuel mass flow rate to the thrus t force generated.Also, it is sometimes called the thrust specific fuel consumption (TSFC). TSFC=mfT However, in turbopropeller jet engines, it is the ratio of the fuel mass flow rate to the power generated in the engine shaft by the turbomachinery. It is sometimes referred to as the brake-specific fuel consumption (BSFC). TFSC=mfSP 2. 2. Fuel and Propellants for Jet Engines Fuels can implicitly be defined as substances used to add heat energy to a system through combustion or other processes. Fuels are mostly hydrocarbons like kerosene, diesel, petrol, alcohol, paraffin and butane and can also be in the form of individually free reactive molecular substances like hydrogen or chemical composites like natural gas, coal, wood.The gaseous state substances used as fuels such as hydrogen, and natural gas (94% methane and 6% ethane) are usually made into a cryogenic state as in liquefied at very low temperature because of their low boiling point. It can easily be asserted by anyone that t he only purpose that fuels have in jet engines is to add energy but little do they know that the purposes grows as the speed of the aircraft increases. For instance, Kerrebrock (2002) stated that supersonic aircrafts which attains very high stagnation temperature that can create destabilization to the airframe structure, engine component and organic substances like lubricants, uses its fuel as a coolant to this parts or components.The energy added by the fuel burned per unit mass of air flow is called the heating value of the fuel and it is a very crucial parameter to be defined before any combustion process analysis is done on a jet engine since it shows how complete the combustion process is through efficiency. The heating value can either be said to be higher or lower depending on if the water product of combustion is a vapour or a liquid. Since the combustion process in jet engine produces vaporised water, the lower heating value of the fuel is used. The most frequently used fue ls for jet engines are kerosene jet A1, A2, JP10 and many more but diesel can also be used. The disadvantages of these fuels are their inevitable emission of toxic substances that contribute to greenhouse effect and their risk of depletion.Accordingly, this has been the driving force for the use of alternative fuels such as cryogenic hydrogen and natural gas which is believed will reduce toxic emissions. Besides, hydrogen is a carbon-free energy carrier and possesses almost no risk of toxic emission since most of its combustion product will be water Chiesa and Laozza (2005). Chapter 3 Turbofan Jet Engine 3. 1. Introduction Between 1936 and the next decade when turbofan engines were invented, people showed little or no interest in them as they described them to be a complicated version of a turbojet engine. However, in 1956, the benefits of turbofan engines started to be noticed as major companies like Rolls-Royce and General Electric began manufacturing them.Since then, it is been o ne of the most used jet engine for commercial purposes because of its low fuel consumption and less noise production. In fact, it has been concluded to be the most reliable jet engine ever manufactured El –Sayed (2008). The turbofan jet engine gas generator unit comprises of a fan unit, compressor section, combustion chamber and turbine unit. Fundamentally, a turbofan jet engine operates as a result of the compressors pressuring air and supplying it afterwards for further processing. The majority of the pressurised air is bypassed around the core of the engine through a duct to be mixed or exhausted whereas the rest of it flows into the main engine core where it combusts with the fuel in the combustion chamber.The hot expanded gas products from the combustion process passes through the turbine thereby rotating the turbine as it leaves the engine. Consequently, the rotating turbine spins the engine spool which in turn rotates the other turbo machinery in the engine. This cause s the front fan to pressurise more and more air into the engine for the process to start all over again in continuous state. The turbofan engine is believed to be the perfect combination of the turboprop and turbojet engine and as a result, its advantages are usually compared to that of the turboprop and turbojet. In fact, Kerrebrock (1992) said that turbofan engine provides a better way of improving the propulsive efficiency of a basic turbojet.It is asserted that at low power setting, low altitude condition and low speed, the turbofan engine is more fuel efficient and has better performance than a turbojet engine. Unlike turboprop engine where vibration occurs in the propeller blades at relative low velocities, the fan in the turbofan engine can attain high relative velocities of Mach 0. 9 before vibration occurs. Also, since the fan in turbofan engines has many blades, it is more stable than the single propeller so even if the vibration velocity is reached, the vibration will not destabilize the airflow because the vibrations are almost negligible. Since the flow into the diffuser of the turbofan is usually subsonic, there very slim chances of shock waves being developed at the entrance. 3. 2. Classification of Turbofan EnginesThere are various types of turbofan engine ranging from high and low bypass ratio, afterburning and non-afterburning, mixed and unmixed flow with multi-spool, after fan and geared or ungeared. The classification of the various types of turbofan engines is shown below in figure 1. Nonetheless, the type of turbofan engine that would be used for the purpose of this dissertation is a forward fan two spool mixed flow turbofan engine. This type of turbofan engine was chosen because it is the compromise of a simple and complex turbofan engine. This is said because it comprises of almost all the classes of a turbofan which are low bypass ratio, forward fan with mixed flow, twin spool with ungeared fan.Moreover, because of the mixed flow intro duced, it produces additional thrust in the hot nozzle compared to the high bypass and it can also permit the addition of afterburner which produces a lot of thrust while consuming a lot of fuel which makes it suitable for military application which shows little worry on fuel consumption. In essence, carrying out a study on this type of turbofan engine will be of great relevance to the military air force sector especially if new research is discovered. TURBOFAN ENGINES Low Bypass Ratio Aft Fan Forward Fan Nonafterburning Afterburning High Bypass Ratio Geared Fan Single Spool Short Duct Ungeared Fan Two Spool Mixed Fan and Core Flow Unmixed Flow Long Duct Three SpoolFigure 1 Classification of Turbofan Jet Engines (El-sayed, 2008) 3. 3. Major Components of Turbofan Engine 3. 4. 1. Diffuser or Inlet Diffuser is the first component that air encounters as it flows into the engine. Basically, the purpose of a diffuser is to suck in air smoothly into the engine, reduce the velocity of the air, increase the static pressure of the air and finally, supply the air in a uniform flow to the compressor. Given the fact that overall performance of an engine is highly dependent on the pressure supplied to the burner, it is necessary to design a diffuser that incurs the minimum amount of pressure loss.To demonstrate this, Flack (2005) stated that if the diffuser incurs a large total pressure loss, the total pressure in the burner will be reduced by the compressor total pressure ratio time this loss. In other words, a small pressure drop in the diffuser can translate into a significant drop in the total pressure supplied to the burner. Another point taken into consideration when designing a diffuser is the angle because if the angle is too big, there will be tendency of eddy flow generation due to early separation. The major causes of pressure losses in the diffuser are as follows. First, losses due to generation of shock waves outside the diffuser and it majorly occur in super sonic diffusers.Secondly, the loss due to the unfavourable or adverse pressure gradient of the diffuser geometry which makes the flow separate a lot earlier and generates eddies. This separation causes a convergent area which makes the velocity not to be reduced by much. Due to the separation, the wall shear deteriorates the static pressure even further. Further analysis done by El-Sayed (2008), describes ways of accounting for this losses like using Fanno line flow and combined area and friction. Thermodynamic Process Equation In this analysis, the loss due to heat transfer is negligible so the process can be adiabatic. The initial kinetic energy is used to raise the static pressure p0 to the total pressure ? =pt2pt0 (inlet pressure recovery) efficiency ? d=IdealReal=ht2s-h0ht2-h0 assuming the gas is ideal and the specific heat at constant pressure is constant efficiency ? d=Tt2s-T0Tt2-T0 simplifying the equation given that ht0=ht2=ht2s and Tt2=Tt0and pt2s=pt2 TtT0=1+? -12M02 and T tT0=ptp0? -1? pt2p0=1+ ? d? -12M02 -1 3. 4. 2. Fan And Compressors Compressor is a very crucial component for the operation of an engine in the sense that it prepares the air for the combustion process in the burner. The main purpose of a compressor as the first rotating component is to use its rotating blades to add kinetic energy to the air and later translate it into total pressure increase.There are basically two types of compressors which are the centrifugal and the axial compressor. Firstly, centrifugal compressor as the name implies changes the direction of an axial airflow to a radial outflow of the air. It was the early compressors adapted in jet engines. It comprises of three main parts which are the impellers, the diffusers and the compressor manifold. The purpose of the impeller is to change the direction of the flow from axial to radial and at the same time increases its static pressure. The diffuser slows down the airflow and further increase the static pressure as it is supplied axially by the compressor manifold to the combustion chamber.The centrifugal compressor is advantageous because the cost of manufacturing it is low compared to axial compressor and as a result is suitable for small engines like turboshafts and turboprops. It is also advantageous because the pressure ratios at single stage are higher than that of the axial compressor. The centrifugal compressor has the tendency of attaining low flow rates and as a result is ideally suitable for helicopters and small aircrafts which require low flow rates. On the other hand, the centrifugal compressor cannot attain high pressure ratio and so it is not suitable when high peak efficiency is required. It incurs a lot of losses due to the change in direction. Secondly, an axial compressor is the most reliable type of compressor and is usually applied when higher pressure ratios of up to 40:1 are required.An axial compressor does not change the axial flow direction of the air but increases the total pressure. Indeed, an axial compressor comprises of three major components which are the rotor with blades, stator can and the inlet guide vane. A stage is a combination of a stator and a rotor. The assembly of the full rotor blade and stator can form the number of stages in a compressor and the greater the number of stages, the higher the total pressure ratio. In this arrangement, the air flows into the inlet guide vane and then into the rotor and stator assembly where compression starts. Also, the length of the rotor and stator reduces along the whole unit which signifies a reduction in volume which induces the increase in pressure.A fan or low pressure compressor is a type of axial compressor but the only differences are that the blades are longer, the total pressure ratio is lower than the typical compressor and the number of stages is usually 1 or 2. The main purpose of creating a fan is to compress more air and to create a bypass air which can be used to generate addition thrust or used for mixing process. Fan Equation Process Given that, isentropic efficiency ? fan= Ideal CycleActual cycle=ht3s-ht2ht3-ht2 Since the specific heat is constant, the equation deduces to ? fan=Tt3s-Tt2Tt3-Tt2 Simplifying the equation whenpt3s=pt3, Tt3sTt2=pt3pt2? -1? , ? fan=pt3pt2 and ? fan=Tt3Tt2 ? fan=? fan? -1? -1? fan-1 Bypass Ratio=msma where ms is the bypass flow rate and ma is the engine core flow rate.For the high pressure compressor, the equations remain the same as that of the fan except the changes in station numbering and the bypass ratio. 3. 4. 3. Combustion Chamber/ Burner The combustion chamber as the Brayton cycle implies is the only source of heat energy addition to the system. Accordingly, the combustion chamber causes very significant increase in the temperature of the air which results in the air gaining enormous internal energy. This energy gained is extracted to be used to power the turbine while the rest is used to create highly accelerated gases from the nozzle. There are three types of combustor namely; the can combustor, the annular combustor and the cannular combustor.The main considerations when designing a combustion chamber is to ensure that the combustion process is complete with no fuel waste, the combustor should have long life materials because any failure can lead to engine explosion. The other consideration is that the air must be heated enough above the ignition fuel temperature in order to ensure stoichiometric combustion. Equations of the Combustion Chamber In the real process of the combustor, total and static pressure drops and the temperature also drop. The major causes of pressure losses are the high level of irreversibility or non-isentropic process and viscous effects in the burner. The burner pressure ratio ? =pt5pt4Burner temperature ratio ? b=Tt5Tt4 Since no work is done only heat transfer, the efficiency of the burner is analysed using the heating value NCV of the fuel used. Thus, efficiency ? b=hea t addedHeating value of fuel=ma+mfht5-maht4NCVmf Given that f=mfma, ? b= 1+fht5- ht4NCVf Equivalence Ratio of combustion It is the ratio of the actual fuel to air ratio of the combustion process to the stoichiometric fuel to air ratio. This ratio produces a means of classifying the combustion process to show whether it is a lean, rich or stoichiometric combustion. The mathematical expression for this is as shown below ? =Actual FARStiochiometric FAR 1 Rich combustion process 3. 4. 4. Turbine Turbine can simply be said to be the antonym of a compressor. In response, a turbine extracts molecular kinetic energy from the air and uses it to drive the turbo machineries which results in the pressure and temperature of the air to drop. If truth be told, Flack (2005) asserted that the turbine uses 70% to 80% of the total energy gained by the air in the combustion chamber to drive the turbo machineries while the remaining 20% to 30% is used to generate thrust in the nozzle.Since the geometry of a turbine have favourable pressure gradient unlike the compressor which is adverse, the efficiency of the turbine is usually very high. Since the turbine is the opposite of the compressor, it has exactly the same configuration of rotor and stator but the volume increase across it which induces the pressure drop. One major problem faced when design a turbine is the deterioration of the blades due to high inlet temperature from the combustion chamber. Based on this, (Song et al. 2002) demonstrated that General Electric uses about 16. 8% of the compressor air to cool the turbine blades of GE 7f engine. Turbine Equation Analysis Given that, Turbine efficiency ? T=ActualIdeal=ht6-ht5ht6s-ht5 T=Tt6-Tt5Tt6s-Tt5 Simplifying the equation given that pt6s=pt6 Tt6sTt5=pt6pt5? -1? ?T=pt6pt5 ? T=Tt6Tt5 ?T=? T-1? T? -1? -1 3. 4. 5. Exhaust Nozzle The nozzle is the final component of the jet engine that the air passes through. The main purposes of the nozzle is to add extra acceleration to the h igh velocity exiting air, reduces its total pressure to that of ambient condition and finally generate sufficient thrust. There are two conditions that occur in the exit of the nozzle depending on the ambient pressure. The first condition is termed under-expansion which occurs when the ambient pressure is less than the exit pressure of the gases.The result of this is that the exit velocity will be lower than it normally is and this makes the momentum component of thrust to be lower than ideal. On the other hand, it will create a positive thrust component for the pressure terms. The second case termed as overexpansion which occurs when the ambient pressure is greater than the exit pressure of the gases. Consequentially, the opposite of what happens in the under-expansion condition occurs where the pressure term is lower and the momentum is higher. Nozzle efficiency ? n=ActualIdeal=ht8-h9ht8-h9s=Tt8-T9Tt8-T9s for constant specific heat Using the steady state energy equation and balanc ing it out, U9=2ht8-h9 . When specific heat is constant U9=2cpTt8-T9 p9pt8=T9sTt8? -1? T9Tt8=11+? -12M92 p9pt8=11+? -12M92-1+ ? n ? n 3. 4.Thermodynamic Process and Cycle of Twin Spool Mixed Flow Turbofan Engine Before any explanation is done from Figure 2, the blue arrows represent the incoming air into the diffuser and the red represent the air flow into the core of the engine while the black arrow represent the bypass air flow through the fan. Finally, the brown arrow represents the air flow after the bypass air and the core air flow have mixed. Based on the arrangement of the turbofan engine in figure 2, it can be seen that air at ambient condition is sucked into the diffuser where the air velocity is reduced and some of its kinetic energy is used to increase the static pressure to the total pressure. The air exiting the diffuser enters the fan or low pressure compressor where it is compressed. Indeed, the molecules of the air gains kinetic and internal energy by colliding rapid ly with one another and as a result increase the enthalpy and static pressure.Also, in the fan, some of the compressed air is bypassed through a duct to be used for the mixing process later while the rest of the air enters into the high pressure compressor of the engine core. In the high pressure compressor, the air is further compressed where the enthalpy and pressure increases as it is released into the combustion chamber. Also, in the high pressure compressor, some of the air mass flow rate is bled out to be used to cool the turbine blades and for air conditioning in the aircraft. In the combustion chamber, the incoming fuel reacts with the air in an oxidation process at constant pressure where the by-product gases gain molecular kinetic energy thereby increasing the enthalpy.This high temperature gases escapes into the high pressure turbine where it is expanded and the gases lose some of their kinetic molecular energy as it enthalpy and static pressure reduces. In other words, i t can be said that the molecular kinetic energy of the gases is being converted to mechanical work which is used to power the high pressure spool. Consequently, the gases enters into the low pressure turbine where it is further expanded to a lower pressure and enthalpy as their molecular kinetic energy is converted to mechanical work to power the low pressure spool. These gases escaping from the low pressure turbine enters the mixing zone or mixer after it has lost most of its total enthalpy and mixes with the bypassed cold air from the duct to further reduce its enthalpy as that of the cold air increases.In other words, the cold air absorbs some of the heat energy from the hot gases until they both attain equilibrium enthalpy. The mixture of the cold air and hot gases both escape at the same equilibrium enthalpy and pressure through the nozzle where their velocity is increased and the pressure is reduced considerably to that of the ambient condition. Furthermore, the exhausted high velocity gases is used to produced thrust for propulsion according to Newton’s third law of motion (In every action, there is equal and opposite reaction). 2 4. 5 6 4 13 0 HPC DIFFUSER FAN/LPC HPT LPT NOZZLE COMBUSTION CHAMBER 2. 5 3 5 8 16 BYPASS DUCT HP Spool LP Spool MIXING ZONEFigure 2 Layout of a Forward Fan Twin Spool Mixed Flow Turbofan Engine P0 P3 P4. 5 P5 P8 P6 P2. 5 P2 P13 P4 ENTROPY (S)(kJ/kg) TEMPERATURE (K) Figure 3 T-S Diagrams for the Forward Fan Twin Spool Mixed Flow Turbofan Engine Chapter 4 Mathematical and Gas Turb 11 Modelling of the Engine 4. 1. Station Numbering and Assumptions Station numbering is a very crucial step that has to be taken when analysis of any thermodynamic system involving many processes is to be done. Moreover, station numbering contributes immensely to showing how the properties of one process relate to another and how the interaction between these processes derives the functional relationship of the thermodynamic system.Returning to the work in hand, the station numbering system that has been adopted for this work on a JT8D-15A turbofan engine is in accordance with the Aerospace Recommended Practice (ARP) and it is shown in figure 2. Assumptions The following assumption were made based on Mattingly (2002) and Kurzke (2007) in order to perform the modelling as listed below * The air flow through the engine is assumed to be steady and one dimensional * The fan and the low pressure Compressor are driven by the low pressure turbine * The overall engine is assumed to have no bleeds in mass flow or power off-take in turbine. * The nozzle of the engine is choked which means the exit pressure will be greater than the ambient pressure. The air is assumed to act as a half ideal gas where the specific heat and ratio is dependent on temperature only. * The areas of each station of the engine is assumed to be constant 4. 2. Design Point Cycle Analysis of the Turbofan Engine The off-design or performance cycle analysis cann ot be done without the design point cycle being defined. The design point cycle in this analysis is obtained using exactly the same data used in the actual test analysis for a JT8D-15A turbofan engine operating at sea level with maximum take-off thrust as shown in (â€Å"JT8D Typical Temperature and Pressure†) and (â€Å"ICAO†). Some of the input parameters such as the isentropic efficiencies and pressure ratios from the actual test data had to be calculated.Since not all the input parameters were given from the actual test data, some of the parameters like inlet corrected mass flow rate, diffuser pressure ratio and efficiency; mechanical spool efficiency had to be guessed in order to complete the analysis and the data are represented below in Table 1. With all the Input Parameter being specified as shown in table 1, the design point cycle simulation of the JT8D-15A turbofan Engine using the Gas Turb 11 software can then be performed. All the steps taken to model the m ixed flow turbofan engine on Gas Turb 11 is clearly represented in the algorithm shown in figure 3 below. COMPONENT| INPUT PARAMETER| | DIFFUSER| Pressure Ratio (? d)| 1| | Inlet Corrected Mass Flow Rate (mc2)| 138. 618 kg/s| FAN| Pressure Ratio (? fan)| 2. 054| | Isentropic Efficiency (? fan)| 0. 78| | Bypass Ratio (? )| 1. 08| Low Pressure Compressor (LPC)| Pressure Ratio (? LPC)| 4. 7| | Isentropic Efficiency (? LPC)| 0. 88| | Nominal Low Pressure Shaft Speed (NLP)| 8160RPM| High Pressure Compressor (HPC)| Pressure Ratio (? HPC)| 3. 77| | Isentropic Efficiency (? HPC)| 0. 864| | Nominal Low Pressure Shaft Speed (NHP)| 11420RPM| Combustion Chamber (cc)| Pressure Ratio (? CC)| 0. 934| | Isentropic Efficiency (? CC)| 0. 99| | Burner Exit Temperature (TIT)| 1277. 15K| High Pressure Turbine (HPT)| Isentropic Efficiency (? HPT)| 0. 9| | HP Spool Mechanical efficiency (? m)| 1| Low Pressure Turbine (LPT)| Isentropic Efficiency (? LPT)| 0. 91| | LP Spool Mechanical efficiency (? m)| 1| T able 1 Input Parameters for the Design Point Cycle Simulation STARTSpecify all the input data gotten from the actual test data as shown in Table 1 Run the Gasturb 11 software and select mixed flow turbofan from the drag down Tab list. Set the scope to ‘More’, set the Calculation Mode as Design and click ‘Run’ Choose the Units to either Imperial or SI and Select the type of fuel from to drop down list to Kerosene, Natural Gas or Hydrogen Estimate the inlet Corrected mc2 Mass Flow rate to the FAN/LPC Choose ‘Single Cycle’ for ‘Select a Task ‘Option and click ‘Run’ Check if the Thrust, SFC, ? HPT, ? LPT and EPR are within (0-10) % of the actual test Experiment END YES NO Figure 4 Design Point Cycle Simulation Algorithm Using Gas Turb 11 Verification of the Design Point simulation ResultsSince not all the input parameters were specified in the actual test data and some of them had to be guessed, it is without any doubt that errors are bound to generate in the simulation results using the Gas Turb 11 software. In order to ensure that the errors accumulated in the simulation were within range, the major output parameters obtained such as net thrust, fuel flow rate, Engine exit pressure ratio, etc were compared to the actual test data as shown in Table 2 and the error range was calculated to be between 0. 25% to 8. 5% which is within an acceptable range. PARAMETERS| ACTUAL TEST DATA| SIMULATED DATA USING GASTURB 11| Net Thrust| 69307. 74| 69320| Engine Exit Pressure Ratio P8P0| 2. 09| 2. 167|Burner Fuel Flow| 1. 100843| 1. 09781| HPT pressure Ratio (? HPT)| 0. 415| 0. 449| LPT Pressure Ratio (? LPT)| 0. 3294| 0. 3514| HPT temperature Ratio (? HPT)| 0. 8097| 0. 8435| LPT temperature Ratio (? LPT)| 0. 7718| 0. 793| Table 2 Comparison Table for the Actual Test Data and Simulated Data Using GasTurb 11 4. 3. Off-Design Point Cycle Simulation of the Turbofan Engine The off-design or performance cycle simulatio n takes into account the concept of module matching of each component through performance maps. This cycle analysis enables the determination of different operating point of the engine at a given design point of the engine.Considering the work in hand, the design point have been defined and verified for the JT8D-15A turbofan engine operating at sea level with maximum take-off thrust which means that different operating points of the engine can be defined with the concept of off-design module matching of the engine. Indeed, the off-design operating point that was considered for the parametric analysis in this work was 30,000ft at M0 0. 8 for the turbofan engine. The off-design modelling of the JT8D-15A engine for the operating point of 30,000ft at M0 0. 8 based on the reference design point defined earlier is clearly demonstrated as follows. The off-design performance cycle simulation may contain some errors because of the component performance maps that were used for the simulation. 4. 3. 1. Module/Component Matching This process only applies to the off-design performance cycle point of the engine.It can simply be defined as the act of synchronising each component of a jet engine to coexist as a unit in order to derive the overall performance characteristics of the jet engine. Component matching involves the process closely studying the ramifications of the actual jet engine overall performance behaviour on the components major characteristics such as pressure ratio, temperature ratio, efficiency and spool speed. This process introduces the concept of empirically determined component performance maps that establishes the relationship between the thermodynamic properties and the geometry of the jet engine itself. 4. 3. 2. Off-Design Component Modelling Diffuser The diffuser was assumed to be adiabatic and the pressure ratio ? d=1 The Isentropic Efficiency was assumed to be 1 For Sea Level,Pamb=101325pa , Tamb=288. 15K For 30,000ft and M0 0. 8, Tamb=288. 15-0. 0 065? 9144 =288. 15-59. 436 =228. 71K Pamb=101325? Tamb288. 155. 2561 =30. 09kpa Tt1=228. 71? 1+? -12M02 =228. 71? 1+1. 4-12? 0. 82 =258K pt1p0=1+ ? d? -12M02 -1 pt1=30. 09? 1+ 1? 1. 4-120. 821. 41. 4-1 pt1=45. 8674kPa pt1=pt2 Tt1=Tt2 Fan and Low Pressure Compressor The inlet corrected mass flow rate is estimated as 138. 618kg/s , As for the off design simulation using the component performance maps for the altitude of 30000ft and Mach no. 0. 8, the actual spool speeds and inlet mass flow rate are calculated based on the estimated inlet corrected mass flow rate as shown below.Low and High pressure spool mechanical efficiency is assumed to be=1 HP spool Speed=11420RPM, LP spool Speed=8160RPM m2=Pt2PSTD? mc2Tt2TSTD =45. 878101. 325? 138. 618258288. 15 Actual Mass flow rate m2=66. 3323kg/s N=Tt2TSTD? NcLP=228. 71288. 15? 8160=7722 RPM The calculated actual mass flow rate and spool speed were used to evaluation the isentropic efficiency and the pressure ratio of the LPC for that operatin g condition from the compressor performance map. Figure 5 Example of a Compressor Performance Map/Curve The diagram above in figure 4 depicts a typical compressor performance map that was used for the off-design point analysis in this work.It can be seen that the x-axis represents the inlet corrected mass flow rate mc2 into the compressor, the y-axis represents the compressor pressure, the red contour lines represents the isentropic efficiencies and the black curved lines represent the relative corrected spool speed. To add to that, the red dash line that ends the speed lines and efficiency lines represent the surge margin which is also known as the stall line that must be avoided since the flow will become unstable in that region. In this work, the inlet corrected mass flow rate and spool speed were calculated which were interpolated on the performance map to obtain the pressure ratio and the isentropic efficiency.For instance, the yellow dot on the map represents a design point tr aced for a given pressure ratio, High Pressure Compressor The inlet corrected mass flow rate into the HPC mc2. 5=mc21+? mc2. 5=138. 6182. 08=66. 64kgs m2. 5=Pt2. 5PSTD? mc2. 5Tt2. 5TSTD N=Tt2. 5TSTD? NcHP The same equation used for the LPC is used to calculate the actual mass flow rate and spool speed which is used to evaluate the isentropic efficiency and pressure ratio when it is operating at an altitude of 30000ft at M0 =0. 8. Verification of the off-design modelling for 30000ft at Mo 0. 8 In order to verify the simulation result gotten for the operational design point of 30000ft at M0 0. , the actual test data results gotten from Mattingly, Heiser and Pratt (2002) for the same operating condition was compared. Due to the difficulties in obtaining a lot of output parameters for this operating point, the result will be verified with only the net thrust generated and the specific fuel consumption. Indeed, the error accumulated was 1. 71% for the net thrust and 0. 83% for the specif ic fuel consumption. PARAMETERS| ACTUAL TEST DATA| SIMULATED DATA USING GASTURB 11| Net Thrust (lb)| 4920| 4836| Specific Fuel Consumption(lb/lbh)| 0. 779| 0. 7855| Table 3 Comparison Table for the Actual Test Data and Simulated Off-design Data Using GasTurb 11 Chapter 5Methodology, Results and Discussions Given that the design point of the JT8D-15A turbofan engine at sea level has been obtained and verified with the actual test data, the operating point of 30000ft at M0 0. 8 was simulated and obtained which now served as the design point for the analysis in this work. Moreover, the procedure taken to define this design point of 30000ft at M0 0. 8 of the JT8D-15A turbofan engine has been clearly stated earlier which gives the permission to conduct the parametric cycle study of the turbofan engine. The parametric cycle studies were done for three different cases for the operational design point of 30000ft at M0 0. of the JT8D-15A turbofan engine as explained as follows. 1. The first parametric analysis case 1 aim to create an understanding of the effects of varying major design parameters on the performance parameters of the turbofan engine when some of the design choices are kept constant. In other words, the bypass ratio and thermal limit parameter (turbine inlet temperature) were varied when the design choices such as the compressor pressure ratio, fan pressure ratio and isentropic efficiencies were kept constant in order to investigate their effects on the performance parameters such as the net thrust, specific fuel consumption, propulsive efficiency, thermal efficiency, and fuel-air-ratio.Much interest is shown nowadays in using alternative fuels like hydrogen and Natural gas in efforts to reduce the cancer known as pollution and the risk of depletion of energy resources. Based on this, conducting a research that focuses of comparing different fuels consumption rate, their risk of pollution and their contribution to the performance of the engine will be re ally valuable. Based on this, a parametric analysis had to be done on the JT8D-15A turbofan engine using three different fuels which are the design point fuel kerosene, hydrogen and natural gas. Since the original design point of the JT8D-15A turbofan was obtained using kerosene fuel, the design points of using hydrogen and natural gas was obtained using the same design choices as that of kerosene.Now that the design points of the JT8D-15A turbofan engine had been defined when using the three different fuels, it had given a go ahead to perform whatever parametric cycle studies of the turbofan engine using the three fuels. In order to compare the performance characteristics of the turbofan engine when it is using the three different fuels, different approaches had to be devised to compare them effectively on a rational basis which defines the last two parametric analysis cases as follows. 2. The second case of parametric analysis was that the fuel flow rate would be kept constant for the three fuels that would be used as the bypass ratio is varied with design choices remaining the same. 3.The third case of study was to make the energy supply into the combustion chamber of the turbofan engine the sa