In order to reduce the pollutant emission and alleviate the pressure of petroleum resources shortage and greenhouse gas emission at the same time,the use of clean and renewable alternative fuel for marine engines is a...In order to reduce the pollutant emission and alleviate the pressure of petroleum resources shortage and greenhouse gas emission at the same time,the use of clean and renewable alternative fuel for marine engines is a promising option.In this study,a marine diesel engine,which was modified to run in diesel methanol compound combustion (DMCC) mode,was investigated.After the diesel injection parameters were calibrated,and combined with a sample after-treatment device DOC (diesel oxidation catalyst),the engine could meet the requirements of China II legislation.The overall MSP (methanol substitute percent) reached 54.1%.The value of each pollutant emission was much lower than that in China II emission legislation,and there was almost no methanol and formaldehyde emissions.When methanol was injected into the inlet manifold,the intake air temperature decreased a lot,as well as the exhaust gas temperature,which were beneficial to increase engine thermal efficiency and improve engine room environment.Compared with the engine running in pure diesel mode,when the engine ran in diesel/methanol dual fuel mode,the combustion phase was advanced,and the combustion duration became shorter.Therefore,the engine thermal efficiency increased,and fuel consumption decreased significantly.展开更多
The design of an annular combustion chamber in a gas turbine engine is thebackbone of this paper.It is specifically designed for a low bypass turbofan engine in a jettrainer aircraft.The combustion chamber is position...The design of an annular combustion chamber in a gas turbine engine is thebackbone of this paper.It is specifically designed for a low bypass turbofan engine in a jettrainer aircraft.The combustion chamber is positioned in between the compressor and turbine.lt has to be designed based on the constant pressure,enthalpy addition process.The presentmethodology deals with the computation of the initial design parameters from benchmarking ofreal-time industry standards and arriving at optimized values.It is then studied for feasibilityand finalized.Then the various dimensions of the combustor are calculated based on differentempirical formulas.The air mass flow is then distributed across the zones of the combustor.The cooling requirement is met using the cooling holes.Finally the variations of parameters atdifferent points are calculated.The whole combustion chamber is modeled using Siemens NX8.0,a modeling software and presented.The model is then analyzed using various parametersat various stages and levels to determine the optimized design.The aerodynamic flowcharacteristics is simulated numerically by means of ANSYS 14.5 software suite.The air-fuelmixture,combustion-turbulence,thermal and cooling analysis is carried out.The analysis isperformed at various scenarios and compared.The results are then presented in image outputsand graphs.展开更多
A numerical simulation of a single cylinder research diesel engine fuelled by natural gas and diesel oil in dual fuel mode was conducted to test the reaction mechanism presented by Li and Williams in Ref.[1]for methan...A numerical simulation of a single cylinder research diesel engine fuelled by natural gas and diesel oil in dual fuel mode was conducted to test the reaction mechanism presented by Li and Williams in Ref.[1]for methane ignition.The mechanism made of only 9 reactions can represent a good compromise between reduction of computational time and accuracy of results.Simulations reproduce test cases previously carried out experimentally and numerically with a simpler kinetic mechanism at three different premixed ratios(10%,15% and 22%).Finally,a last case characterized by a supply of methane consistent with the typical load levels for this kind of engines(80%),was investigated only numerically.All the simulations were performed with the KIVA-3V solver on a geometry which includes open valve periods,intake and exhaust ducts.Through a comparison between experimental and numerical results,a calibration of the model has been performed and a quite good fitting of the models has been achieved.展开更多
基金financial support provided by the Natural Science Foundation of China (No.51676134)。
文摘In order to reduce the pollutant emission and alleviate the pressure of petroleum resources shortage and greenhouse gas emission at the same time,the use of clean and renewable alternative fuel for marine engines is a promising option.In this study,a marine diesel engine,which was modified to run in diesel methanol compound combustion (DMCC) mode,was investigated.After the diesel injection parameters were calibrated,and combined with a sample after-treatment device DOC (diesel oxidation catalyst),the engine could meet the requirements of China II legislation.The overall MSP (methanol substitute percent) reached 54.1%.The value of each pollutant emission was much lower than that in China II emission legislation,and there was almost no methanol and formaldehyde emissions.When methanol was injected into the inlet manifold,the intake air temperature decreased a lot,as well as the exhaust gas temperature,which were beneficial to increase engine thermal efficiency and improve engine room environment.Compared with the engine running in pure diesel mode,when the engine ran in diesel/methanol dual fuel mode,the combustion phase was advanced,and the combustion duration became shorter.Therefore,the engine thermal efficiency increased,and fuel consumption decreased significantly.
文摘The design of an annular combustion chamber in a gas turbine engine is thebackbone of this paper.It is specifically designed for a low bypass turbofan engine in a jettrainer aircraft.The combustion chamber is positioned in between the compressor and turbine.lt has to be designed based on the constant pressure,enthalpy addition process.The presentmethodology deals with the computation of the initial design parameters from benchmarking ofreal-time industry standards and arriving at optimized values.It is then studied for feasibilityand finalized.Then the various dimensions of the combustor are calculated based on differentempirical formulas.The air mass flow is then distributed across the zones of the combustor.The cooling requirement is met using the cooling holes.Finally the variations of parameters atdifferent points are calculated.The whole combustion chamber is modeled using Siemens NX8.0,a modeling software and presented.The model is then analyzed using various parametersat various stages and levels to determine the optimized design.The aerodynamic flowcharacteristics is simulated numerically by means of ANSYS 14.5 software suite.The air-fuelmixture,combustion-turbulence,thermal and cooling analysis is carried out.The analysis isperformed at various scenarios and compared.The results are then presented in image outputsand graphs.
文摘A numerical simulation of a single cylinder research diesel engine fuelled by natural gas and diesel oil in dual fuel mode was conducted to test the reaction mechanism presented by Li and Williams in Ref.[1]for methane ignition.The mechanism made of only 9 reactions can represent a good compromise between reduction of computational time and accuracy of results.Simulations reproduce test cases previously carried out experimentally and numerically with a simpler kinetic mechanism at three different premixed ratios(10%,15% and 22%).Finally,a last case characterized by a supply of methane consistent with the typical load levels for this kind of engines(80%),was investigated only numerically.All the simulations were performed with the KIVA-3V solver on a geometry which includes open valve periods,intake and exhaust ducts.Through a comparison between experimental and numerical results,a calibration of the model has been performed and a quite good fitting of the models has been achieved.
