Numerical Investigation of the Effect of Hydrogen Enrichment on an Opposed-Piston Compression Ignition Diesel Engine
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摘要
High power-to-weight and fuel efficiency are bounded with opposed-piston compression ignition(OPCI) engine, which makes it ideal in certain applications. In the present study, a dynamic three-dimensional CFD model was established to numerically investigate the combustion process and emission formation of a model OPCI engine with hydrogen enrichment. The simulation results indicated that a small amount of hydrogen was efficient to improve the indicated power owing to the increased in-cylinder pressure. Hydrogen tended to increase the ignition delay of diesel fuel due to both dilution and chemical effect. The burning rate of diesel fuel was apparently accelerated when mixing with hydrogen and premixed combustion became dominated. NO_x increased sharply while soot was sufficiently suppressed due to the increase of in-cylinder temperature. Preliminary modifications on diesel injection strategy including injection timing and injection pressure were conducted. It was notable that excessive delayed injection timing could reduce NO_x emission but deteriorate the indicated power which was mainly attributed to the evident decline of hydrogen combustion efficiency. This side effect could be mitigated by increasing the diesel injection pressure. Appropriate delay of injection coupled with high injection pressure was suggested to deal with trade-offs among NO_x, soot and engine power.
High power-to-weight and fuel efficiency are bounded with opposed-piston compression ignition(OPCI) engine, which makes it ideal in certain applications. In the present study, a dynamic three-dimensional CFD model was established to numerically investigate the combustion process and emission formation of a model OPCI engine with hydrogen enrichment. The simulation results indicated that a small amount of hydrogen was efficient to improve the indicated power owing to the increased in-cylinder pressure. Hydrogen tended to increase the ignition delay of diesel fuel due to both dilution and chemical effect. The burning rate of diesel fuel was apparently accelerated when mixing with hydrogen and premixed combustion became dominated. NO_x increased sharply while soot was sufficiently suppressed due to the increase of in-cylinder temperature. Preliminary modifications on diesel injection strategy including injection timing and injection pressure were conducted. It was notable that excessive delayed injection timing could reduce NO_x emission but deteriorate the indicated power which was mainly attributed to the evident decline of hydrogen combustion efficiency. This side effect could be mitigated by increasing the diesel injection pressure. Appropriate delay of injection coupled with high injection pressure was suggested to deal with trade-offs among NO_x, soot and engine power.
High power-to-weight and fuel efficiency are bounded with opposed-piston compression ignition(OPCI) engine, which makes it ideal in certain applications. In the present study, a dynamic three-dimensional CFD model was established to numerically investigate the combustion process and emission formation of a model OPCI engine with hydrogen enrichment. The simulation results indicated that a small amount of hydrogen was efficient to improve the indicated power owing to the increased in-cylinder pressure. Hydrogen tended to increase the ignition delay of diesel fuel due to both dilution and chemical effect. The burning rate of diesel fuel was apparently accelerated when mixing with hydrogen and premixed combustion became dominated. NO_x increased sharply while soot was sufficiently suppressed due to the increase of in-cylinder temperature. Preliminary modifications on diesel injection strategy including injection timing and injection pressure were conducted. It was notable that excessive delayed injection timing could reduce NO_x emission but deteriorate the indicated power which was mainly attributed to the evident decline of hydrogen combustion efficiency. This side effect could be mitigated by increasing the diesel injection pressure. Appropriate delay of injection coupled with high injection pressure was suggested to deal with trade-offs among NO_x, soot and engine power.
引文
[1]Pirault J.P.,Flint M.,Opposed piston engines:evolution,use,and future applications.New ed.edition,SAEinternational,New York,2010.
[2]Abani N.,Nagar N.,Zermeno R.,Thomas I.,Developing a 55%BTE commercial heavy-duty opposed-piston engine without a waste heat recovery system.SAETechnical Paper,2017-01-0638,2017.
[3]Naik S.,Johnson D.,Koszewnik J.,Fromm L.,Redon F.,Regner G.,et al.,Practical applications of opposed-piston engine technology to reduce fuel consumption and emissions.SAE Technical Paper,2013-01-2754,2013.
[4]Kalkstein J.,R?ver W.,Campbell B.,et al.,Opposed piston opposed cylinder(opoc?)5/10 kW heavy fuel engine for UAVs and APUs.SAE Technical Paper,2006-01-0278,2006.
[5]Peng L.,Tusinean A.,Hofbauer P.,Deylami K.,Development of a compact and efficient truck APU.SAETechnical Paper,2005-01-0653,2005.
[6]Hofbauer P.,Opposed piston opposed cylinder(OPOC)engine for military ground vehicles.SAE Technical Paper,2005-01-1548,2005.
[7]Zhang L.,Su T.X.,Zhang Y.A.,Ma F.K.,Yin J.G.,Feng Y.N.,Numerical investigation of the effects of split injection strategies on combustion and emission in an opposed-piston,opposed-cylinder(OPOC)two-stroke diesel engine.Energies,2017,10(5):684.
[8]Zhang Z.Y.,Chi Y.C.,Shang L.J.,Zhang P.,Zhao Z.F.,On the role of droplet bouncing in modeling impinging sprays under elevated pressures.International Journal of Heat and Mass Transfer,2016,102:657-668.
[9]Zhang Z.,Zhang P.,Zhao Z.,Spray impingement and combustion in a model opposed-piston compression ignition engine.Combustion Science and Technology,2017,189(11):1943-1965.
[10]Zhou J.H.,Cheung C.S.,Zhao W.Z.,Leung C.W.,Diesel-hydrogen dual-fuel combustion and its impact on unregulated gaseous emissions and particulate emissions under different engine loads and engine speeds.Energy,2016,94:110-123.
[11]Quadri S.A.P.,Masood M.,Kumar P.R.,Effect of pilot fuel injection operating pressure in hydrogen blended compression ignition engine:An experimental analysis.Fuel,2015,157:279-284.
[12]Shin B.,Cho Y.,Han D.,Song S.,Chun K.M.,Hydrogen effects on NOx emissions and brake thermal efficiency in a diesel engine under low-temperature and heavy-EGRconditions.International Journal of Hydrogen Energy,2011,36:6281-6291.
[13]Fang W.,Huang B.,Kittelson D.B.,Northrop W.F.,Dual-fuel diesel engine combustion with hydrogen,gasoline,and ethanol as fumigants:effect of diesel injection timing.Journal of Engineering for Gas Turbines and Power,2014,136(8):081502.
[14]Banerjee R.,Roy S.,Bose P.K.,Hydrogen-EGR synergy as a promising pathway to meet the PM-NOx-BSFC tradeoff contingencies of the diesel engine:A comprehensive review.International Journal of Hydrogen Energy,2015,40(37):12824-12847.
[15]Amrouche F.,Erickson P.,Park J.,Varnhagen S.,An experimental investigation of hydrogen-enriched gasoline in a Wankel rotary engine.International Journal of Hydrogen Energy,2014,39(16):8525-8534.
[16]Fan B.W.,Pan J.F.,Yang W.M.,Zhu Y.J.,Chen W.,Effects of hydrogen blending mode on combustion process of a rotary engine fueled with natural gas/hydrogen blends.International Journal of Hydrogen Energy,2016,41(6):4039-4053.
[17]Yuan C.H.,Han C.J.,Xu J.,Numerical evaluation of pilot-ignition technology used for a hydrogen fuelled free piston engine generator.International Journal of Hydrogen Energy,2017,42(47):28599-28611.
[18]Beale J.C.,Modeling spray atomization with the Kelvin Helmholtz/Rayleigh-Taylor hybrid model.Atomization and Sprays,1999,9(6):623-650.
[19]Schmidt D.P.,Rutland C.J.,A new droplet collision algorithm.Journal of Computational Physics,2000,164(1):62-80.
[20]Han Z.,Reitz R.D.,Turbulence modeling of internal combustion engines using RNGκ-εmodels.Combustion Science and Technology,1995,106(4-6):267-295.
[21]Senecal P.K.,Pomraning E.,Richards K.J.,Briggs T.E.,Choi C.Y.,Mcdavid R.M.,et al.,Multi-dimensional modeling of direct-injection diesel spray liquid length and flame lift-off length using CFD and parallel detailed chemistry.SAE Technical Paper,2003-01-1043,2003.
[22]An H.,Yang W.M.,Maghbouli A.,Li J.,Chou S.K.,Chuaa K.J.,et al,Numerical investigation on the combustion and emission characteristics of a hydrogen assisted biodiesel combustion in a diesel engine.Fuel,2014,120:186-194.
[23]Ahmadi R.,Hosseini S.M.,Numerical investigation on adding/substituting hydrogen in the CDC and RCCIcombustion in a heavy duty engine.Applied Energy,2018,213:450-468.
[24]Sharma P,Dhar A,Compression ratio influence on combustion and emissions characteristic of hydrogen diesel dual fuel CI engine:Numerical Study.Fuel,2018,222:852-858.
[25]Hockett A.,Hampson G.,Marchese A.J.,Development and validation of a reduced chemical kinetic mechanism for computational fluid dynamics simulations of natural gas/diesel dual-fuel engines.Energy&Fuels,2016,30(3):2414-2427.
[26]Kaminaga T.,Kusaka J.,Ishii Y.,A three-dimensional numerical study on exhaust gas emissions from a medium-duty diesel engine using a phenomenological soot particle formation model combined with detailed chemistry.International Journal of Engine Research,2008,9(4):283-296.
[27]Heywood J.B.,Internal combustion engine fundamentals.McGraw Hill,New York,1988.
[28]Huo M.,Huang Y.,Hofbauer P.,Piston design impact on the scavenging and combustion in an opposed-piston,opposed-cylinder(opoc)two-stroke engine.SAETechnical Paper,2015-01-1269,2015.
[29]Franke M.,Huang H.,Liu J.P.,Geistert A.,Adomeit P.,Opposed piston opposed cylinder(opoc?)450 hp engine:performance development by CAE simulations and testing.SAE Technical Paper,2006-01-0277,2006.
[30]Zhou J.H.,Cheung C.S.,Leung C.W.,Combustion,performance and emissions of a diesel engine with H2,CH4 and H2-CH4 addition.International Journal of Hydrogen Energy,2014,39(9):4611-4621.
[31]Zhou J.H.,Cheung C.S.,Leung C.W.,Combustion,performance,regulated and unregulated emissions of a diesel engine with hydrogen addition.Applied Energy,2014,126:1-12.
[32]Hamdan M.O.,Selim M.Y.E.,Al-Oman S.A.B.,Elnajjar E.,Hydrogen supplement co-combustion with diesel in compression ignition engine.Renewable Energy,2015,82:54-60.
[33]Guo H.S.,Neill W.S.,The effect of hydrogen addition on combustion and emission characteristics of an n-heptane fuelled HCCI engine.International Journal of Hydrogen Energy,2013,38(26):11429-11437.
[34]Jeftic M.,Reader G.T.,Zheng M.,Impacts of low temperature combustion and diesel post injection on the in-cylinder production of hydrogen in a lean-burn compression ignition engine.International Journal of Hydrogen Energy,2017,42:1276-1286.
[35]Gatts T.,Liu S.Y.,Liew C.,Ralston B.,Bell C.,Li H.L.,An experimental investigation of incomplete combustion of gaseous fuels of a heavy-duty diesel engine supplemented with hydrogen and natural gas.International Journal of Hydrogen Energy,2012,37:7848-7859.
[36]Maghbouli A.,Yang W.M.,An H.,Shafee S.,Li J.,Mohammadi S.,Modeling knocking combustion in hydrogen assisted compression ignition diesel engines.Energy,2014,76:768-779.
[37]Pandey P.,Pundir B.P.,Panigrahi P.K.,Hydrogen addition to acetylene-air laminar diffusion flames:Studies on soot formation under different flow arrangements.Combustion Flame,2007,148:249-262.
[38]Park S.H.,Lee K.M.,Hwang C.H.,Effects of hydrogen addition on soot formation and oxidation in laminar premixed C2H2/air flames,International Journal of Hydrogen Energy,2011,36:9304-9311.
[39]Guo H.S.,Liu F.S.,Smallwood G.J.,Gulder O.L.,Numerical study on the influence of hydrogen addition on soot formation in a laminar ethylene-air diffusion flame.Combustion and Flame,2006,145:324-338.
[40]Du W.,Lou J.J.,Yan Y.,Bao W.H.,Liu F.S.,Effects of injection pressure on diesel sprays in constant injection mass condition.Applied Thermal Engineering,2017,121:234-241.
[41]Benajes J.,Martin J.,Garcia A.,Villalta D.,Warey A.,Swirl ratio and post injection strategies to improve late cycle diffusion combustion in a light-duty diesel engine.Applied Thermal Engineering,2017,123:365-376.
[42]Shimura M.,Johchi A.,Tanahashi M.,Consumption rate characteristics of a fine-scale unburnt mixture in a turbulent jet premixed flame by high repetition rate PLIFand SPIV.Journal of Thermal Science and Technology,2016,11(3):JTST0047.
[2]Abani N.,Nagar N.,Zermeno R.,Thomas I.,Developing a 55%BTE commercial heavy-duty opposed-piston engine without a waste heat recovery system.SAETechnical Paper,2017-01-0638,2017.
[3]Naik S.,Johnson D.,Koszewnik J.,Fromm L.,Redon F.,Regner G.,et al.,Practical applications of opposed-piston engine technology to reduce fuel consumption and emissions.SAE Technical Paper,2013-01-2754,2013.
[4]Kalkstein J.,R?ver W.,Campbell B.,et al.,Opposed piston opposed cylinder(opoc?)5/10 kW heavy fuel engine for UAVs and APUs.SAE Technical Paper,2006-01-0278,2006.
[5]Peng L.,Tusinean A.,Hofbauer P.,Deylami K.,Development of a compact and efficient truck APU.SAETechnical Paper,2005-01-0653,2005.
[6]Hofbauer P.,Opposed piston opposed cylinder(OPOC)engine for military ground vehicles.SAE Technical Paper,2005-01-1548,2005.
[7]Zhang L.,Su T.X.,Zhang Y.A.,Ma F.K.,Yin J.G.,Feng Y.N.,Numerical investigation of the effects of split injection strategies on combustion and emission in an opposed-piston,opposed-cylinder(OPOC)two-stroke diesel engine.Energies,2017,10(5):684.
[8]Zhang Z.Y.,Chi Y.C.,Shang L.J.,Zhang P.,Zhao Z.F.,On the role of droplet bouncing in modeling impinging sprays under elevated pressures.International Journal of Heat and Mass Transfer,2016,102:657-668.
[9]Zhang Z.,Zhang P.,Zhao Z.,Spray impingement and combustion in a model opposed-piston compression ignition engine.Combustion Science and Technology,2017,189(11):1943-1965.
[10]Zhou J.H.,Cheung C.S.,Zhao W.Z.,Leung C.W.,Diesel-hydrogen dual-fuel combustion and its impact on unregulated gaseous emissions and particulate emissions under different engine loads and engine speeds.Energy,2016,94:110-123.
[11]Quadri S.A.P.,Masood M.,Kumar P.R.,Effect of pilot fuel injection operating pressure in hydrogen blended compression ignition engine:An experimental analysis.Fuel,2015,157:279-284.
[12]Shin B.,Cho Y.,Han D.,Song S.,Chun K.M.,Hydrogen effects on NOx emissions and brake thermal efficiency in a diesel engine under low-temperature and heavy-EGRconditions.International Journal of Hydrogen Energy,2011,36:6281-6291.
[13]Fang W.,Huang B.,Kittelson D.B.,Northrop W.F.,Dual-fuel diesel engine combustion with hydrogen,gasoline,and ethanol as fumigants:effect of diesel injection timing.Journal of Engineering for Gas Turbines and Power,2014,136(8):081502.
[14]Banerjee R.,Roy S.,Bose P.K.,Hydrogen-EGR synergy as a promising pathway to meet the PM-NOx-BSFC tradeoff contingencies of the diesel engine:A comprehensive review.International Journal of Hydrogen Energy,2015,40(37):12824-12847.
[15]Amrouche F.,Erickson P.,Park J.,Varnhagen S.,An experimental investigation of hydrogen-enriched gasoline in a Wankel rotary engine.International Journal of Hydrogen Energy,2014,39(16):8525-8534.
[16]Fan B.W.,Pan J.F.,Yang W.M.,Zhu Y.J.,Chen W.,Effects of hydrogen blending mode on combustion process of a rotary engine fueled with natural gas/hydrogen blends.International Journal of Hydrogen Energy,2016,41(6):4039-4053.
[17]Yuan C.H.,Han C.J.,Xu J.,Numerical evaluation of pilot-ignition technology used for a hydrogen fuelled free piston engine generator.International Journal of Hydrogen Energy,2017,42(47):28599-28611.
[18]Beale J.C.,Modeling spray atomization with the Kelvin Helmholtz/Rayleigh-Taylor hybrid model.Atomization and Sprays,1999,9(6):623-650.
[19]Schmidt D.P.,Rutland C.J.,A new droplet collision algorithm.Journal of Computational Physics,2000,164(1):62-80.
[20]Han Z.,Reitz R.D.,Turbulence modeling of internal combustion engines using RNGκ-εmodels.Combustion Science and Technology,1995,106(4-6):267-295.
[21]Senecal P.K.,Pomraning E.,Richards K.J.,Briggs T.E.,Choi C.Y.,Mcdavid R.M.,et al.,Multi-dimensional modeling of direct-injection diesel spray liquid length and flame lift-off length using CFD and parallel detailed chemistry.SAE Technical Paper,2003-01-1043,2003.
[22]An H.,Yang W.M.,Maghbouli A.,Li J.,Chou S.K.,Chuaa K.J.,et al,Numerical investigation on the combustion and emission characteristics of a hydrogen assisted biodiesel combustion in a diesel engine.Fuel,2014,120:186-194.
[23]Ahmadi R.,Hosseini S.M.,Numerical investigation on adding/substituting hydrogen in the CDC and RCCIcombustion in a heavy duty engine.Applied Energy,2018,213:450-468.
[24]Sharma P,Dhar A,Compression ratio influence on combustion and emissions characteristic of hydrogen diesel dual fuel CI engine:Numerical Study.Fuel,2018,222:852-858.
[25]Hockett A.,Hampson G.,Marchese A.J.,Development and validation of a reduced chemical kinetic mechanism for computational fluid dynamics simulations of natural gas/diesel dual-fuel engines.Energy&Fuels,2016,30(3):2414-2427.
[26]Kaminaga T.,Kusaka J.,Ishii Y.,A three-dimensional numerical study on exhaust gas emissions from a medium-duty diesel engine using a phenomenological soot particle formation model combined with detailed chemistry.International Journal of Engine Research,2008,9(4):283-296.
[27]Heywood J.B.,Internal combustion engine fundamentals.McGraw Hill,New York,1988.
[28]Huo M.,Huang Y.,Hofbauer P.,Piston design impact on the scavenging and combustion in an opposed-piston,opposed-cylinder(opoc)two-stroke engine.SAETechnical Paper,2015-01-1269,2015.
[29]Franke M.,Huang H.,Liu J.P.,Geistert A.,Adomeit P.,Opposed piston opposed cylinder(opoc?)450 hp engine:performance development by CAE simulations and testing.SAE Technical Paper,2006-01-0277,2006.
[30]Zhou J.H.,Cheung C.S.,Leung C.W.,Combustion,performance and emissions of a diesel engine with H2,CH4 and H2-CH4 addition.International Journal of Hydrogen Energy,2014,39(9):4611-4621.
[31]Zhou J.H.,Cheung C.S.,Leung C.W.,Combustion,performance,regulated and unregulated emissions of a diesel engine with hydrogen addition.Applied Energy,2014,126:1-12.
[32]Hamdan M.O.,Selim M.Y.E.,Al-Oman S.A.B.,Elnajjar E.,Hydrogen supplement co-combustion with diesel in compression ignition engine.Renewable Energy,2015,82:54-60.
[33]Guo H.S.,Neill W.S.,The effect of hydrogen addition on combustion and emission characteristics of an n-heptane fuelled HCCI engine.International Journal of Hydrogen Energy,2013,38(26):11429-11437.
[34]Jeftic M.,Reader G.T.,Zheng M.,Impacts of low temperature combustion and diesel post injection on the in-cylinder production of hydrogen in a lean-burn compression ignition engine.International Journal of Hydrogen Energy,2017,42:1276-1286.
[35]Gatts T.,Liu S.Y.,Liew C.,Ralston B.,Bell C.,Li H.L.,An experimental investigation of incomplete combustion of gaseous fuels of a heavy-duty diesel engine supplemented with hydrogen and natural gas.International Journal of Hydrogen Energy,2012,37:7848-7859.
[36]Maghbouli A.,Yang W.M.,An H.,Shafee S.,Li J.,Mohammadi S.,Modeling knocking combustion in hydrogen assisted compression ignition diesel engines.Energy,2014,76:768-779.
[37]Pandey P.,Pundir B.P.,Panigrahi P.K.,Hydrogen addition to acetylene-air laminar diffusion flames:Studies on soot formation under different flow arrangements.Combustion Flame,2007,148:249-262.
[38]Park S.H.,Lee K.M.,Hwang C.H.,Effects of hydrogen addition on soot formation and oxidation in laminar premixed C2H2/air flames,International Journal of Hydrogen Energy,2011,36:9304-9311.
[39]Guo H.S.,Liu F.S.,Smallwood G.J.,Gulder O.L.,Numerical study on the influence of hydrogen addition on soot formation in a laminar ethylene-air diffusion flame.Combustion and Flame,2006,145:324-338.
[40]Du W.,Lou J.J.,Yan Y.,Bao W.H.,Liu F.S.,Effects of injection pressure on diesel sprays in constant injection mass condition.Applied Thermal Engineering,2017,121:234-241.
[41]Benajes J.,Martin J.,Garcia A.,Villalta D.,Warey A.,Swirl ratio and post injection strategies to improve late cycle diffusion combustion in a light-duty diesel engine.Applied Thermal Engineering,2017,123:365-376.
[42]Shimura M.,Johchi A.,Tanahashi M.,Consumption rate characteristics of a fine-scale unburnt mixture in a turbulent jet premixed flame by high repetition rate PLIFand SPIV.Journal of Thermal Science and Technology,2016,11(3):JTST0047.