环境气体对氢气喷射与卷吸特性的影响
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摘要
基于RANS方法对氢气在氩气和氮气氛围下的高压喷射过程进行仿真,研究了压力、温度和激波对氢气射流喷射和卷吸特性的影响.研究表明:射流贯穿距由于马赫盘的存在而呈现三阶段变化.在不同喷射压力下,射流前期卷吸能力随着喷嘴压力比(NPR)的增加而增大,而后期呈现相反趋势.在相同密度下,激波影响射流前期卷吸效果,但随着射流发展效果逐渐减弱.温度升高,氢气射流的贯穿距明显增大,但射流卷吸能力也显著降低.此外,氢气射流在氮气氛围下的卷吸环境气体物质的量和卷吸能力均强于氩气氛围.
The hydrogen jets under argon and nitrogen atmosphere were simulated by the RANS method.The effects of gas pressure,gas temperature and shock wave on spray and entrainment characteristics of hydrogen jet were studied.It is found that the penetration of the jet presents three stages of changes due to the Mach disk.The entrainment capacity of the jet at different injection pressures increases with the increase of the nozzle pressure ratio(NPR)in the early stage but the opposite trend in the later stage.Under the same density,the shock wave affects the entrainment in the early stage of jet,but the effect gradually decreases with the development of jet.With the increase of temperature,the penetration of hydrogen jet increases obviously,but the jet entrainment capacity decreases significantly.In addition,the entrainment amount of ambient gas and the entrainment capacity of hydrogen jet under a nitrogen atmosphere are both stronger than those under an argon atmosphere.
The hydrogen jets under argon and nitrogen atmosphere were simulated by the RANS method.The effects of gas pressure,gas temperature and shock wave on spray and entrainment characteristics of hydrogen jet were studied.It is found that the penetration of the jet presents three stages of changes due to the Mach disk.The entrainment capacity of the jet at different injection pressures increases with the increase of the nozzle pressure ratio(NPR)in the early stage but the opposite trend in the later stage.Under the same density,the shock wave affects the entrainment in the early stage of jet,but the effect gradually decreases with the development of jet.With the increase of temperature,the penetration of hydrogen jet increases obviously,but the jet entrainment capacity decreases significantly.In addition,the entrainment amount of ambient gas and the entrainment capacity of hydrogen jet under a nitrogen atmosphere are both stronger than those under an argon atmosphere.
引文
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[15]Vuorinen V,Yu J,Tirunagari S,et al.Large-eddy simulation of highly underexpanded transient gas jets[J].Physics of Fluids,2013,25(1):281-319.
[2]Killingsworth N J,Rapp V H,Flowers D L,et al.Increased efficiency in SI engine with air replaced by oxygen in argon mixture[J].Proceedings of the Combustion Institute,2011,33(2):3141-3149.
[3]邓俊,龚学海,詹羽,等.氩-氧氛围下天然气缸内燃烧特性试验[J].内燃机学报,2017,35(1):38-43.
[4]Moneib H A,Abdelaal M,Selim M Y E,et al.NOx,emission control in SI engine by adding argon inert gas to intake mixture[J].Energy Conversion&Management,2009,50(11):2699-2708.
[5]Sharma T K.Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture[J].Journal of Advanced Research,2015,6(6):819-826.
[6]Welch A,Mumford D,Munshi S,et al.Challenges in developing hydrogen direct injection technology for internal combustion engines[C]//SAE Paper.Shanghai,China,2008,2008-01-2379.
[7]Mohammadi A,Shioji M,Nakai Y,et al.Performance and combustion characteristics of a direct injection SIhydrogen engine[J].International Journal of Hydrogen Energy,2007,32(2):296-304.
[8]Hamzehloo A,Aleiferis P.Computational study of hydrogen direct injection for internal combustion engines[C]//SAE Paper.Seoul,Korea,2013,2013-01-2524.
[9]Hamzehloo A,Aleiferis P G.Large eddy simulation of highly turbulent under-expanded hydrogen and methane jets for gaseous-fuelled internal combustion engines[J].International Journal of Hydrogen Energy,2014,39(36):21275-21296.
[10]Hamzehloo A,Aleiferis P G.Numerical modelling of transient under-expanded jets under different ambient thermodynamic conditions with adaptive mesh refinement[J].International Journal of Heat&Fluid Flow,2016,61(B):711-729.
[11]Otobe Y,Kashimura H,Matsuo S,et al.Influence of nozzle geometry on the near-field structure of a highly under-expanded sonic jet[J].Journal of Fluids&Structures,2008,24(2):281-293.
[12]Ewan B C R,Moodie K.Structure and velocity measurements in underexpanded jets[J].Combustion Science&Technology,1986,45(5/6):275-288.
[13]Crist S,Glass D R,Sherman P M.Study of the highly underexpanded sonic jet[J].AIAA Journal,1966,4(1):68-71.
[14]Hamzehloo A,Aleiferis P G.Gas dynamics and flow characteristics of highly turbulent under-expanded hydrogen and methane jets under various nozzle pressure ratios and ambient pressures[J].International Journal of Hydrogen Energy,2016,41(15):6544-6566.
[15]Vuorinen V,Yu J,Tirunagari S,et al.Large-eddy simulation of highly underexpanded transient gas jets[J].Physics of Fluids,2013,25(1):281-319.