The Experts below are selected from a list of 183 Experts worldwide ranked by ideXlab platform
Petros Lappas - One of the best experts on this subject based on the ideXlab platform.
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An Exhaust heat recovery system utilising thermoelectric generators and heat pipes
Applied Thermal Engineering, 2017Co-Authors: Aliakbar Akbarzadeh, Petros LappasAbstract:Exhaust heat recovery systems are used to make use of otherwise wasted heat from a car engine. The purpose of Exhaust heat recovery systems is to potentially reduce the fuel consumption of the car and consequently reduce CO2 emissions and running costs. The system design described herein utilises thermoelectric generators (TEGs) and heat pipes with its key advantage being it is a passive solid state design. The use of heat pipes allows for more flexible designs as the TEG location is not limited to the Exhaust pipe surface. Testing was undertaken on a car with a 3.0 L V6 engine. In all test conditions the power loss due to pressure drop in the Exhaust Duct was always lower than the electrical power output. Repeat tests were conDucted and the results were found to be consistent. When testing the system at different orientations, the bottom heat mode was found to be the best option. After all testing, the maximum power output of the system was 38 W from the eight 62 mm × 62 mm TEGs used. The rate of heat transfer in this case was 1541 W with the resultant TEG efficiency being 2.46%. The calculated potential reDuction in CO2 emissions, fuel consumption and fuel costs was 1.57%.
Ozgur Balli - One of the best experts on this subject based on the ideXlab platform.
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comparative performance metric assessment of a military turbojet engine utilizing hydrogen and kerosene fuels through advanced exergy analysis method
Energies, 2020Co-Authors: Burak Yuksel, Ozgur Balli, Huseyin Gunerhan, Arif HepbasliAbstract:This study dealt with evaluating the (J85-GE-5H) military turbojet engine (TJE) in terms of exergetic and advanced exergetic analyses at Military (MIL) and Afterburner (AB) process modes by utilizing kerosene (JP-8) and hydrogen (H2) fuels. First, exergy and advanced exergy analyses of the engine were performed using JP-8 fuel as per actual engine operating conditions. These analyses of the turbojet engine using hydrogen fuel were also examined parametrically. The performance evaluation of the engine was lastly executed by comparing the obtained results for both fuels. Based on the parametric studies undertaken, the entire engine’s exergetic efficiency with JP-8 was reckoned 30.85% at the MIL process mode while it was calculated as 16.98% at the AB process mode. With the usage of H2, the efficiencies of the engine decreased to 28.62% and 15.33% for the above mentioned two modes, respectively. As the supreme exergy destructions occurred in the combustion chamber (CC) and afterburner Exhaust Duct (ABED) segments, the new technological developments should be considered to design more efficient engines. As a result, the engine worked less efficiently with hydrogen fuel due to the enhancement in exergy destructions. Conversely, the greenhouse gas (GHG) emission parameters lessened with the utilization of H2 fuel.
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advanced exergy analyses to evaluate the performance of a military aircraft turbojet engine tje with afterburner system splitting exergy destruction into unavoidable avoidable and endogenous exogenous
Applied Thermal Engineering, 2017Co-Authors: Ozgur BalliAbstract:Abstract A conventional and advanced exergy analysis of a military aircraft turbojet engine is presented in this paper. In this framework, the main exergy parameters of the engine components are introduced while the exergy destruction rates within the engine components are split into endogenous/exogenous and avoidable/unavoidable parts. Also, the mutual interdependencies among the components of the engine and realistic improvement potentials depending on operating conditions are acquired through the analysis. As a result of the study, the exergy efficiency values of the engine are determined to be 39.41% at military (MIL) mode (maximum engine thrust operation without afterburner fuel combustion) and 17.90% at afterburner (AB) mode (maximum engine thrust operation with afterburner fuel combustion), respectively. The system has low improvement potential because the unavoidable exergy destruction rate is 93% at MIL mode and 98% at AB mode. The relationships between the components seem to be weak since the endogenous exergy destruction is 83% at MIL mode and 94% at AB mode. Finally, it may be concluded that the low pressure compressor, the high pressure compressor, the combustion chamber and afterburner Exhaust Duct of the engine should be focused on according to the results obtained.
P.a. Anan'ev - One of the best experts on this subject based on the ideXlab platform.
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The numerical research of the gas flow in the Exhaust Duct of the gas turbine with a waste heat boiler
Ain Shams Engineering Journal, 2016Co-Authors: A.a. Zhinov, D.v. Shevelev, A.k. Karyshev, P.a. Anan'evAbstract:Abstract A gas flow in the Exhaust path of the gas turbine unit GPA-C-16 with a waste heat boiler is investigated. The aim of this study was to optimize geometric characteristics of the waste heat boiler’s gas Duct. A flow in the Exhaust stack has been simulated by CFD. For turbulence modeling the standard k–e model was used. Analysis of the results allowed us to optimize the waste heat boiler.
Arif Hepbasli - One of the best experts on this subject based on the ideXlab platform.
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comparative performance metric assessment of a military turbojet engine utilizing hydrogen and kerosene fuels through advanced exergy analysis method
Energies, 2020Co-Authors: Burak Yuksel, Ozgur Balli, Huseyin Gunerhan, Arif HepbasliAbstract:This study dealt with evaluating the (J85-GE-5H) military turbojet engine (TJE) in terms of exergetic and advanced exergetic analyses at Military (MIL) and Afterburner (AB) process modes by utilizing kerosene (JP-8) and hydrogen (H2) fuels. First, exergy and advanced exergy analyses of the engine were performed using JP-8 fuel as per actual engine operating conditions. These analyses of the turbojet engine using hydrogen fuel were also examined parametrically. The performance evaluation of the engine was lastly executed by comparing the obtained results for both fuels. Based on the parametric studies undertaken, the entire engine’s exergetic efficiency with JP-8 was reckoned 30.85% at the MIL process mode while it was calculated as 16.98% at the AB process mode. With the usage of H2, the efficiencies of the engine decreased to 28.62% and 15.33% for the above mentioned two modes, respectively. As the supreme exergy destructions occurred in the combustion chamber (CC) and afterburner Exhaust Duct (ABED) segments, the new technological developments should be considered to design more efficient engines. As a result, the engine worked less efficiently with hydrogen fuel due to the enhancement in exergy destructions. Conversely, the greenhouse gas (GHG) emission parameters lessened with the utilization of H2 fuel.
Eric Domingues - One of the best experts on this subject based on the ideXlab platform.
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Volumetric efficiency optimization of a single-cylinder D.I. diesel engine using differential evolution algorithm
Applied Thermal Engineering, 2016Co-Authors: Stephan Hennings Och, Luis Mauro Moura, Viviana Cocco Mariani, Leandro Dos Santos Coelho, José Antonio Velásquez, Eric DominguesAbstract:Abstract In this work, a mathematical optimization procedure was used to improve the gas exchange process of a single-cylinder compression ignition naturally aspirated engine. Duct lengths and valve timing were chosen as optimization variables while volumetric efficiency was defined as the objective function. Calculations were carried out using a parallelized computational code consisting of (i) a one-dimensional model for the unsteady compressible gas flow taking place in intake and Exhaust Ducts; (ii) a single-zone combustion model for the in-cylinder processes; and (iii) an optimization routine based on the Differential Evolution technique. Three sets of optimization calculations were conDucted. In the first one, the intake Duct length was the only optimization variable and it was found that optimal inlet Duct lengths vary becoming shorter as engine speed is increased. In the second set of calculations, both intake and Exhaust Duct lengths have been taken as the optimization variables, and the resulting optimal intake Duct lengths were quite similar to those of the first set. In addition, optimal Exhaust Duct lengths resulted very close in value to optimal intake Duct lengths, except at the highest speeds, when the decreasing tendency as engine speed is raised was supplanted by the opposite tendency. In the third set of calculations, the crank angles defining valve synchronism were the optimization variables. It was found that optimal valve timing produced a gain in volumetric efficiency, which is similar to that obtained with optimal Duct lengths.