Yazar "Gonca, Guven" seçeneğine göre listele

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    The Effects of Equivalence Ratio and Temperature of Different Fuel Mixtures on the Performance and NO Emission Characteristics of a Spark Ignition Engine
    (Springer Heidelberg, 2024) Gonca, Guven; Sahin, Bahri; Hocaoglu, Mehmet Fatih
    This study examines the impacts of equivalence ratio and temperature for different liquid-gas fuel mixtures such as hydrogen, methane, propane and benzene, ethanol, gasoline, hexane, isooctane, methanol and toluene on the variation of power output, thermal efficiency, efficiency of exergy (second law efficiency) and NO formation were examined. The mixtures consist of 50% of liquid fuels and 50% of gaseous fuels. The results revealed that the equivalence ratios and fuel temperatures remarkably affect the NO and performance of the spark ignition engine. The minimum values of performance characteristics of the fuels are attained at 1.5 of equivalence ratio. Maximum power output values are observed at 1 of the equivalence ratio. Power, thermal and exergy efficiencies decrease with increasing fuel temperatures. However, NO formation has reverse relation with temperature. Maximum and minimum values of power output are 16.21 kW and 1.03 kW which are observed with toluene-hydrogen and methanol-hydrogen mixtures. Maximum and minimum values of thermal efficiency are 45.04% and 3.29% which are observed with benzene-hydrogen and methanol-hydrogen mixture combustion. The same mixture kinds provided maximum and minimum values of exergy efficiency and NO formation as 45.24-3.28% and 1.83E-06 mol/cm3-2.97E-32 mol/cm3, respectively. In the results, the performance characteristics are changed depending on equivalence ratios and fuel temperatures.
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    Exergetic and Exergo-Economical Analyses of a Gas-Steam Combined Cycle System
    (Walter De Gruyter Gmbh, 2022) Gonca, Guven; Guzel, Bulent
    In this study, the results of an investigation of the performance of a gas-steam combined cycle system (GSCCS) under exergetic and exergo-economical criteria are reported. The effective power (P-ef), destroyed exergy (X), efficiency of exergy (epsilon), unit electric generation cost (C-elec) and exergy-dependent economic worth of electrical energy (C-ex,C-elec), which is novelly determined in this study, have been analyzed. The impacts of speed (N), pressure ratio of the gas cycle (lambda), equivalence ratio (phi), the flow rate of the air mass ((m) over dot(a)), the flow rate of the fuel mass ((m) over dot(f)), inlet temperature of the air into the compressor (T-1), steam temperature (T-6) and pressure (P-6) of the heat exchanger, outlet pressure (P-7) of the high pressure steam turbine and condenser pressure (P-9) on P-ef, epsilon, C-elec and C-ex,C-elec have been parametrically evaluated. It was revealed that the stream and component characteristics of the system have significant influences on the performance characteristics of the GSCCS.
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    Öğe
    Performance investigation and simulation of a diesel engine operating on seven-process cycle based on energy and exergy criteria
    (Inderscience Enterprises Ltd, 2023) Gonca, Guven; Genc, Ibrahim; Sahin, Bahri
    This work investigates energetic and exergetic performances of seven-process cycle which is combination of Dual-Miller and Takemura cycles based on parametrical and grid curves. The impacts of design parameters on the maximum performance characteristics are examined. In the results, the energy (1. law) and exergy (2. law) efficiencies are maximised by a determined range, and then they are minimised by raising engine speed. Power is enhanced by enhancing engine speed at constant compression, Takemura cycle, equivalence, and cut-off ratios. Power and efficiencies increase with raising cycle pressure ratio at constant compression, Takemura cycle, equivalence and pressure ratios. Power and efficiencies decrease with increasing exhaust temperature ratio and cut-off ratio at constant compression ratio, Takemura cycle ratio, equivalence ratio and engine speed. They enhance with increasing pressure ratio and cycle temperature ratio at constant compression ratio, Takemura cycle ratio, engine speed and cut-off ratio.
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    Öğe
    Performance investigation and simulation of a diesel engine operating on seven-process cycle based on energy and exergy criteria
    (Inderscience Enterprises Ltd, 2023) Gonca, Guven; Genc, Ibrahim; Sahin, Bahri
    This work investigates energetic and exergetic performances of seven-process cycle which is combination of Dual-Miller and Takemura cycles based on parametrical and grid curves. The impacts of design parameters on the maximum performance characteristics are examined. In the results, the energy (1. law) and exergy (2. law) efficiencies are maximised by a determined range, and then they are minimised by raising engine speed. Power is enhanced by enhancing engine speed at constant compression, Takemura cycle, equivalence, and cut-off ratios. Power and efficiencies increase with raising cycle pressure ratio at constant compression, Takemura cycle, equivalence and pressure ratios. Power and efficiencies decrease with increasing exhaust temperature ratio and cut-off ratio at constant compression ratio, Takemura cycle ratio, equivalence ratio and engine speed. They enhance with increasing pressure ratio and cycle temperature ratio at constant compression ratio, Takemura cycle ratio, engine speed and cut-off ratio.
  • Küçük Resim
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    Work density analysis and thermoeconomic optimisation of modified Carnot cycle engine
    (Inderscience Enterprises Ltd, 2023) Karakurt, Asim Sinan; Gonca, Guven; Sahin, Bahri
    The modified Carnot cycle, a novel thermodynamic cycle, is introduced, and the cycle's performance is analysed in order to more accurately depict the performance and design parameters of actual heat engines. Work output, thermal efficiency, and work density are all considered in conjunction during the performance analysis. In terms of maximum pressure, maximum volume, work density, thermal efficiency, and size, the results demonstrate that the modified cycle performs better than the classic Carnot cycle at simulating the real heat engine. In the performance analysis framework, a thermoeconomic optimisation has been carried out based on an objective function defined as the total cost per unit work output, which depends on an economic parameter, work density, and thermal efficiency. The findings might be used to select the modified cycle's ideal design and operation parameters, which can be applied to actual engines.