283 research outputs found
Effect of reference altitudes for a turbofan engine with the aid of specific-exergy based method
No full textWOS: 000311077100008This paper presents effect of reference altitudes on the exergetic efficiency of a engine with the aid of specific exergy method. between 4000-9000 m. In the analysis, and exergy efficiency of the engine is found to be from 50.34% at 4000 m to 48.91% at 9000 m. Results of this study show that increase in reference altitude decreases the exergy efficiency and increases the energy efficiency of the engine. Additionally, specific exergy analysis can also be used as an integrated indicator for determining the exergetic efficiency.Anadolu University in TurkeyThe author would like to thank Anadolu University in Turkey for their financial, technical and knowledge support
An exergy way to quantify sustainability metrics for a high bypass turbofan engine
No full textWOS: 000356986300065As fuel efficiency becomes a greater concern in aero engine design and operation. To meet this need, a new methodology is being developed here that proposes the use of exergetic metrics for mapping the exergy flows throughout high bypass turbofan engine at maximum thrust level for its sustainability assessment. The engine (net thrust force of 206 kN) studied here is used in the first wide body, dual-aisle, and the largest commercial aircraft. The findings of sustainability analysis reveal that exergy efficiency of the engine is 29.6% having exergy destruction factor of 0.5037. In addition, environmental effect factor of the turbofan engine is found to be 0.675, while exergetic sustainability index is calculated to be 1.48. In the case study, recoverable exergy amount of the engine is zero since the emissions released from exhaust cannot be recoverable in the engine. As a conclusion, exergetic sustainability method is an effective way to assess the sustainability of aircraft and aero engines and provides a good tool for designers, users, decision makers and researchers in green air transportation. Hence, these parameters make the engine and aircraft more environmentally benign and more sustainableAnadolu University in Eskisehir city of TurkeyThe author would like to express their appreciation to Anadolu University in Eskisehir city of Turkey for full support throughout the preparation of this study, while he would like to thank the reviewers for their valuable comments, which helped in increasing the quality of the paper
Exergetic effects of some design parameters on the small turbojet engine for unmanned air vehicle applications
No full text6th International Green Energy Conference (IGEC) -- JUN 05-09, 2011 -- Eskisehir, TURKEYWOS: 000311873700007This article analyses some design parameters on the exergetic and energetic performances for a small turbojet engine for unmanned vehicles. On the basis of theoretical data employed, some exergetic and aerothermodynamics aspects of the engine and its components are parametrically studied in terms of compressor pressure ratio (pi(c)) and turbine inlet temperature (T-t4). The results show that mainly based on the operating parameters for 2<pi(c) < 7, 1200 K < T-t4 < 1500 K and thrust range values are in the range of 894-907 N. increasing turbine inlet temperature decreases the exergy efficiency of the small turbojet engine. However, any increase in compressor pressure ratio along with increase in flight Mach number results in an increasing exergy efficiency of the engine. Computer experiments were performed at 9000 m altitude with flight Mach number of 0.8 and 0.9. Studying these parameters indicates how much improvement is possible for the small turbojet engine to achieve better energy and exergy consumptio
Energy and exergy (ENEX) analyses of a MD-80 aircraft
No full textThe growth in demand for air transport is a problem for the global and local environment. There are, moreover, fundamental conflicts with sustainable development objectives. Sustainability demands a sustainable supply of energy without causing negative environmental impacts of aircrafts. In this paper, an investigation of energy and exergy analyses (ENEX) is reported for a MD-80 aircraft at take-offphase. In this regard, considering ENEX equations, exergy and energy efficiencies of the aircraft are found to be 29.8% and 11.48% respectively, while take-offthrust and specific fuel consumption of the MD-80 is to be 144 kN and 14.58 g (kN.s)-1. In addition, fuel and product exergies of the aircraft are calculated to be 93.92 MW and 28.06 M
Exergo-economic analysis of an experimental aircraft turboprop engine under low torque condition
No full textDoga Nanobiotech Inc.1st International Congress on Energy Efficiency and Energy Related Materials, ENEFM 2013 -- 9 October 2013 through 12 October 2013 -- -- 117279Exergo-economic analysis is an unique combination of exergy analysis and cost analysis conducted at the component level. In exergo-economic analysis, cost of each exergy stream is determined. Inlet and outlet exergy streams of the each component are associated to a monetary cost. This is essential to detect costineffective processes and identify technical options which could improve the cost effectiveness of the overall energy system. In this study, exergo-economic analysis is applied to an aircraft turboprop engine. Analysis is based on experimental values at low torque condition (240 N m). Main components of investigated turboprop engine are the compressor, the combustor, the gas generator turbine, the free power turbine and the exhaust. Cost balance equations have been formed for all components individually and exergo-economic parameters including cost rates and unit exergy costs have been calculated for each componen
Numerical calculation of energy and exergy flows of a turboshaft engine for power generation and helicopter applications
No full textWOS: 000388542300079Fuel efficiency of aircraft and helicopter becomes greater concern in recent years caused by rising fuel costs and as well as environmental impact of aviation emissions. Modern helicopters, however, highly complex systems with especially turboshaft engines that produce energy and power. So it is important to gain deeper understanding energy and exergy use throughout turboshaft engine and its components. Concurrently, in this study, energy and exergy-based computational approach applied to a turboshaft engine and its components. Exergy efficiency of the axial, centrifugal compressors and power turbine is found to be between 83.8% and 88.6%, while for the combustor, the corresponding value is to be 80.60%. For the components, the greatest exergy efficiency is calculated to be 91.4% at the gas generator turbine unit. As a result of the study, the exergetic efficiency of the turboshaft has been calculated as 27.5% with 1500 kW product exergy. It is expected that numerical formulation based on energy and exergy is beneficial for assessing turboshaft performance for future rotorcraft developmentTUSAS Engine Industries (TEI); Anadolu University in Eskisehir city of TurkeyThe authors would like to express their appreciation to TUSAS Engine Industries (TEI) and Anadolu University in Eskisehir city of Turkey for full support throughout the preparation of this study
Energy and Entropy Analyses of an Experimental Turbojet Engine For Target Drone Application
No full textThis study investigates energy and entropy analyses of an experimental turbojet engine build in Anadolu University Faculty of Aeronautics and Astronautics Test-Cell Laboratory. Law of motions and Brayton thermodynamic cycle model are used for this purpose. The processes (that is, compression, combustion, and expansion) are simulated in P-v, T-s and h-s diagrams. Furthermore, the second law of thermodynamics is applied to the cycle model to perform the entropy analysis. A distribution of the wasted and thrust power, the overall (energy-based the first law efficiency), and the specific fuel consumption and specific thrust of the engine were calculated during the analyses as well. The results of the study also show the entropy changing value in engine components due to irreversibilities and inefficiencies. As a conclusion, it is expected that this study is useful to study future design and research work similar aircraft turbojets, auxiliary power units and target drone power systems.This study investigates energy and entropy analyses of an experimental turbojet engine build in Anadolu University Faculty of Aeronautics and Astronautics Test-Cell Laboratory. Law of motions and Brayton thermodynamic cycle model are used for this purpose. The processes (that is, compression, combustion, and expansion) are simulated in P-v, T-s and h-s diagrams. Furthermore, the second law of thermodynamics is applied to the cycle model to perform the entropy analysis. A distribution of the wasted and thrust power, the overall (energy-based the first law efficiency), and the specific fuel consumption and specific thrust of the engine were calculated during the analyses as well. The results of the study also show the entropy changing value in engine components due to irreversibilities and inefficiencies. As a conclusion, it is expected that this study is useful to study future design and research work similar aircraft turbojets, auxiliary power units and target drone power systems
Analysis overall efficiency variation with fan pressure ratio and bypass ratio for afterburning and separate flow turbofans
No full textToplam verim, itki sistemi ön tasarımda önemli bir parametredir ve motordan elde edilen itki gücünün motora verilen ısıl enerjiye oranı olarak tanımlanır. Bu çalışmada, ayrık akışlı ve ardyanmalı turbofan motorlarda fan basınç oranı ve bypass oranı değişkenlerinin motorun toplam verimi üzerindeki etkileri araştırılmıştır. Bu amaçla motora ait fan basınç oranı-bypass oranı-toplam verim değişimlerini üç boyutlu gösteren yüzey grafikleri oluşturulmuş ve üç farklı uçuş hızı için bilgisayar deneyleri yapılarak elde edilen sonuçlar yorumlanmıştır.Overall efficiency is an important design parameter of the engine in preliminary design and defined as the ratio of aircraft thrust power to the rate of thermal energy released in the engine. In this paper, effects of the fan pressure ratio and the bypass ratio on engine overall efficiency were investigated for afterburning and separate flow turbofans. With this purpose, fan pressure ratio&#9135;bypass ratio&#9135;overall efficiency three dimensional graphs were developed and then computer experiment results were evaluated for three different flight Mach number
Environmental impact assessment of a turboprop engine with the aid of exergy
No full textWOS: 000323534900066To develop approaches that effectively reduce engine environmental effect of aircrafts, it is necessary to understand the mechanisms that have enabled improvements in thermodynamic efficiency of aircraft engines. In the present work, a turboprop engine used in regional aircrafts that produces 1948 shp and 640 N.m torque is examined using exergo-environmental method. The results show compressor, combustion chamber, gas generator turbine, power turbine and exhaust nozzle create 9%, 69%, 13%, 7%, 2% of total environmental impact of the engine, respectively. According to rates, the compressor and gas turbine can be considered first to improve in case of component related environmental impact. Furthermore, total component related environmental impact for the turboprop engine is found to be 2.26 mPts/s for the constructional phase and 234 mPts/s for the operation/maintenance phases. Accordingly, it is suggested that, in order to estimate environmental impact metric of aircrafts, the exergo-environmental analysis can be employed for aircraft propulsion system
On-design exergy analysis of a combustor for a turbojet engine: a parametric study
No full text
Purpose
The purpose of this study is to perform an exergy analysis of a turbojet engine combustor at different cycle parameters.
Design/methodology/approach
Base cycle parameters have been defined for the engine, and then differentiation of the combustor exergy efficiencies and destruction rates have been evaluated by changing overall pressure ratio, combustor exit temperature and combustor pressure ratio.
Findings
For the basic engine cycle, combustor unit is found to have lowest exergy efficiency as 62.3 for the sea level static condition. Compressor turbine exhaust and whole engine exergy efficiencies have been calculated as 88.7, 96.5, 68.2 and 69.4, respectively.
Practical implications
Because of the biggest exergy, destruction is seen mainly in combustion system; effect of the combustor inlet pressure (related to the compressor design technology), pressure drop and exit temperature on the exergy efficiencies have been analyzed and combustor second law efficiency have been evaluated.
Social implications
The investigation’s purposes are highly connected with social wellness and targeted at sustainable development of the society. Practical implementation of the obtained scientific results is directed on the improving of combustor for a turbojet engines and decreasing negative influence on the environment.
Originality/value
As a result of this paper, the following are the contribution of this paper in the field of gas turbine exergy subjects: Combustor has been found as the most critical component in respect of the exergy efficiency. Therefore, the effect of the combustor main cycle parameters such as inlet pressure, combustor pressure ratio and exit temperature have been analyzed.
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