基于激波结构的天然气发动机燃气高压喷射特性
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摘要
基于纹影法对0.5、1.0和1.5,MPa共3种气源压力条件下燃气射流诱导激波的特征参数随时间的变化规律进行研究.结果表明:高压脉冲燃气喷射过程存在明显的状态变化,且实际喷射持续期明显大于控制脉宽.随气源压力增加,喷孔入口压力的上升时间增加,处于稳态的时间减小,燃气喷射的瞬态性增强,电磁阀关闭后的低压喷射时间长、减压慢.总体上,从气源到喷孔出口,燃气压力能到动能的转化效率小于50%,,3种气源压力下,出口雷诺数分布在0.5×10~5~2.5×10~5内,与柴油相比,甲烷射流的主动混合能力弱,被动混合能力强.随气源压力增加,马赫盘的宽度增加,进而使射流近场锥角增大,对燃气的湍流混合及空间分布起促进作用.
The time-varying jet induced shock wave characteristics are measured and analyzed under three origin pressure conditions of 0.5,1.0 and 1.5,MPa by means of schlieren imaging method.Results show that the high pressure pulse gas injection process has obvious state change,and the actual injection duration is obviously larger than that of the control pulse width.With the increase of origin pressure,the rising time of the nozzle inlet pressure increases,and the duration of pressure balance at upstream of nozzle decreases.It promotes the transient variation of gas fuel injection.The velocity of gas pressure reduction is very low after the start of the solenoid valve closed,which leads to a very long time for low-pressure gas injection.In general,the conversion efficiency of gas pressure energy to kinetic energy is less than 50%, from the gas source to the outlet of the nozzle.The Reynolds number at exit of the nozzle distributes in the range of 0.5×10~5—2.5×10~5 under three origin pressure conditions.Compared with diesel spray,the active mixing ability of methane jet is weak,and the passive mixing ability is strong.With the increase of origin pressure,Mach disk width increases,which causes the increase of jet near-field angle and promotes the spatial distribution and turbulent mixing of gas jet.
The time-varying jet induced shock wave characteristics are measured and analyzed under three origin pressure conditions of 0.5,1.0 and 1.5,MPa by means of schlieren imaging method.Results show that the high pressure pulse gas injection process has obvious state change,and the actual injection duration is obviously larger than that of the control pulse width.With the increase of origin pressure,the rising time of the nozzle inlet pressure increases,and the duration of pressure balance at upstream of nozzle decreases.It promotes the transient variation of gas fuel injection.The velocity of gas pressure reduction is very low after the start of the solenoid valve closed,which leads to a very long time for low-pressure gas injection.In general,the conversion efficiency of gas pressure energy to kinetic energy is less than 50%, from the gas source to the outlet of the nozzle.The Reynolds number at exit of the nozzle distributes in the range of 0.5×10~5—2.5×10~5 under three origin pressure conditions.Compared with diesel spray,the active mixing ability of methane jet is weak,and the passive mixing ability is strong.With the increase of origin pressure,Mach disk width increases,which causes the increase of jet near-field angle and promotes the spatial distribution and turbulent mixing of gas jet.
引文
[1]苏万华.高密度-低温柴油机燃烧理论与技术的研究与进展[J].内燃机学报,2008,26(S):1-8.
[2]刘涛,纪军,卫海桥,等.先进发动机燃烧基础研究的进展和关键科学问题[J].中国科学基金,2014,X(1):20-25.
[3]解茂昭.内燃机跨临界/超临界燃料喷雾混合过程的机理与模型[J].燃烧科学与技术,2014,20(1):1-8.
[4]Sahoo B B,Sahoo N,Saha U K.Effect of engine parameters and type of gaseous fuel on the performance of dual-fuel gas diesel engines:A critical review[J].Renewable and Sustainable Energy Reviews,2009,13(2):1151-1184.
[5]Bhandari K,Bansal A,Shukla A,et al.Performance and emission of natural gas fueled internal combustion engine:A review[J].Journal of Scientific&Industrial Research,2005,64(1):333-338.
[6]Cho H M,He B Q.Spark ignition natural gas engines:A review[J].Energy Conversion and Management,2007,48(1):608-618.
[7]Munday D,Gutmark E,Liu J,et al.Flow structure and acoustics of supersonic jets from conical convergentdivergent nozzles[J].Physics of Fluids,2011,23(11):106-116.
[8]Panda J,Seasholtz G.Measurement of shock structure and shock-vortex interaction in underexpanded jets using Rayleigh scattering[J].Physics of Fluids,1999,11(12):3761-3777.
[9]Donaldson C D,Snedeker R S.A study of free jet impingement Part 1:Mean properties of free and impinging jets[J].Journal of Fluid Mechanics,1971,45(2):281-319.
[10]Hiller B,Hanson R K.Simultaneous planar measurements of velocity and pressure fields in gas flows using laser-induced fluorescence[J].Applied Optics,1988,27(1):33-48.
[11]Abraham J,Magi V,Maclnnes J,et al.Gas versus spray injection:Which mixes faster[C]//SAE Paper.Detroit,Michigan,USA,1994,940895.
[12]Ouellette P.High pressure injection of natural gas for diesel engine fueling[D].Vancouver:Department of Mechanical Engineering,University of British Columbia,1992.
[13]Rubas P J,Paul M A,Martin G C,et al.Methane jet penetration in a direct-injection natural gas engine[C]//SAE Paper.Detroit,Michigan,USA,1998,980143.
[14]Bruneaux G.A study of mixture formation in direct injection diesel like conditions using quantitative fuel concentration visualizations in a gaseous fuel jet[C]//SAE Paper.Detroit,Michigan,USA,2002,2002-01-1632.
[15]王金华,方宇,黄佐华,等.利用高速摄影纹影法研究天然气高压喷射射流特性[J].内燃机学报,2007,25(6):500-504.
[16]White T R,Milton B E.Shock wave calibration of underexpanded natural gas fuel jets[J].Shock Waves,2008,18(1):353-364.
[17]Yu J Z,Vuorinen V,Kaario O,et al.Characteristics of high pressure jets for direct injection gas engine[C]//SAE Paper.Detroit,Michigan,USA,2013,2013-01-1619.
[18]Yu J Z,Vuorinen V,Kaario O,et al.Visualization and analysis of the characteristics of transitional under expanded jets[J].International Journal of Heat and Fluid Flow,2013,44:140-154.
[19]Mate B,Graur I A,Elizarova T,et al.Experimental and numerical investigation of an axisymmetric supersonic jet[J].Journal of Fluid Mechanics,2001,426(1):177-197.
[20]潘锦珊,单鹏.气体动力学基础[M].北京:国防工业出版社,2012:71-73.
[2]刘涛,纪军,卫海桥,等.先进发动机燃烧基础研究的进展和关键科学问题[J].中国科学基金,2014,X(1):20-25.
[3]解茂昭.内燃机跨临界/超临界燃料喷雾混合过程的机理与模型[J].燃烧科学与技术,2014,20(1):1-8.
[4]Sahoo B B,Sahoo N,Saha U K.Effect of engine parameters and type of gaseous fuel on the performance of dual-fuel gas diesel engines:A critical review[J].Renewable and Sustainable Energy Reviews,2009,13(2):1151-1184.
[5]Bhandari K,Bansal A,Shukla A,et al.Performance and emission of natural gas fueled internal combustion engine:A review[J].Journal of Scientific&Industrial Research,2005,64(1):333-338.
[6]Cho H M,He B Q.Spark ignition natural gas engines:A review[J].Energy Conversion and Management,2007,48(1):608-618.
[7]Munday D,Gutmark E,Liu J,et al.Flow structure and acoustics of supersonic jets from conical convergentdivergent nozzles[J].Physics of Fluids,2011,23(11):106-116.
[8]Panda J,Seasholtz G.Measurement of shock structure and shock-vortex interaction in underexpanded jets using Rayleigh scattering[J].Physics of Fluids,1999,11(12):3761-3777.
[9]Donaldson C D,Snedeker R S.A study of free jet impingement Part 1:Mean properties of free and impinging jets[J].Journal of Fluid Mechanics,1971,45(2):281-319.
[10]Hiller B,Hanson R K.Simultaneous planar measurements of velocity and pressure fields in gas flows using laser-induced fluorescence[J].Applied Optics,1988,27(1):33-48.
[11]Abraham J,Magi V,Maclnnes J,et al.Gas versus spray injection:Which mixes faster[C]//SAE Paper.Detroit,Michigan,USA,1994,940895.
[12]Ouellette P.High pressure injection of natural gas for diesel engine fueling[D].Vancouver:Department of Mechanical Engineering,University of British Columbia,1992.
[13]Rubas P J,Paul M A,Martin G C,et al.Methane jet penetration in a direct-injection natural gas engine[C]//SAE Paper.Detroit,Michigan,USA,1998,980143.
[14]Bruneaux G.A study of mixture formation in direct injection diesel like conditions using quantitative fuel concentration visualizations in a gaseous fuel jet[C]//SAE Paper.Detroit,Michigan,USA,2002,2002-01-1632.
[15]王金华,方宇,黄佐华,等.利用高速摄影纹影法研究天然气高压喷射射流特性[J].内燃机学报,2007,25(6):500-504.
[16]White T R,Milton B E.Shock wave calibration of underexpanded natural gas fuel jets[J].Shock Waves,2008,18(1):353-364.
[17]Yu J Z,Vuorinen V,Kaario O,et al.Characteristics of high pressure jets for direct injection gas engine[C]//SAE Paper.Detroit,Michigan,USA,2013,2013-01-1619.
[18]Yu J Z,Vuorinen V,Kaario O,et al.Visualization and analysis of the characteristics of transitional under expanded jets[J].International Journal of Heat and Fluid Flow,2013,44:140-154.
[19]Mate B,Graur I A,Elizarova T,et al.Experimental and numerical investigation of an axisymmetric supersonic jet[J].Journal of Fluid Mechanics,2001,426(1):177-197.
[20]潘锦珊,单鹏.气体动力学基础[M].北京:国防工业出版社,2012:71-73.