贫燃条件下当量比对等离子体辅助起爆的影响
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摘要
为研究贫燃条件下当量比对交流介质阻挡放电等离子体辅助起爆的影响,采用松耦合方法仿真求解了当量比分别为1.0,0.8及0.6三种条件下氢氧预混气体起爆过程,对比研究了放电产物时空分布特性、不同阶段爆震管内流场参数分布、起爆时间和距离以及推力壁动态历程。结果表明放电产物在同一周期内的时空分布形态不随当量比改变而变化,但随着当量比下降,各主要活性粒子的密度增大,增幅则降低。随着管内流速上升,等离子体对流场结构的改变更加明显,加速了形成稳定爆震波的各个子过程;不同工况下等离子体都缩短了起爆时间和距离,但当量比越低,缩短程度越小。对推力壁受力的动态分析也显示等离子体对流场演化的加速效果随当量比减小而减弱,不过其受力大小与等离子体无关。在本文贫燃条件下出现低当量比不利于等离子体发挥作用的原因包含两点,一是燃料占比降低带来的不利影响大于等离子体助燃的效果,二是放电区域尺寸有限。
Aimed at studying the effects of equivalence ratio on plasma assisted detonation initiation by alternating current dielectric barrier discharge(AC DBD)under lean burn condition,a loosely coupled method was used to simulate the detonation initiation process of a hydrogen-oxygen mixture in a detonation combustor under different equivalence ratios. Three equivalence ratios including 1.0,0.8,and 0.6 are selected in the study.The temporal and spatial distribution characteristics of discharge generated particles,profiles of the combustor flowfield parameters at several representative stages,deflagration to detonation transition(DDT)time and distance,and history of thrust wall pressure are studied in detail. It is found that the pattern of the temporal and spatial distribution of discharge products in one cycle does not change as equivalence ratio decreases,yet the number density of the key active particles increases while the increase amplitude declines. With the flow velocity of combustor increases,the effect of plasma on the flowfield structure becomes more and more notably,and every sub-process of the stable detonation wave forming process is accelerated. The DDT distance and time are both reduced by the plasma for all the cases. However,the reduction amplitude declines when lower the equivalence ratio. Also,it shows that the acceleration effect of plasma on the flowfield evolution weakens with equivalence ratio decreases from the dynamic analysis of the thrust wall pressure,yet the magnitude of pressure is independent of the plasma. The reasons for the phenomenon that the lower equivalence ratio is not conducive to the plasma to play a role in expediting the DDT process under the lean burn condition are as follows: the disadvantage effect brought by the decline of the percentage of fuel is stronger than the effect of plasma assisted combustion,and the discharge area is limited.
Aimed at studying the effects of equivalence ratio on plasma assisted detonation initiation by alternating current dielectric barrier discharge(AC DBD)under lean burn condition,a loosely coupled method was used to simulate the detonation initiation process of a hydrogen-oxygen mixture in a detonation combustor under different equivalence ratios. Three equivalence ratios including 1.0,0.8,and 0.6 are selected in the study.The temporal and spatial distribution characteristics of discharge generated particles,profiles of the combustor flowfield parameters at several representative stages,deflagration to detonation transition(DDT)time and distance,and history of thrust wall pressure are studied in detail. It is found that the pattern of the temporal and spatial distribution of discharge products in one cycle does not change as equivalence ratio decreases,yet the number density of the key active particles increases while the increase amplitude declines. With the flow velocity of combustor increases,the effect of plasma on the flowfield structure becomes more and more notably,and every sub-process of the stable detonation wave forming process is accelerated. The DDT distance and time are both reduced by the plasma for all the cases. However,the reduction amplitude declines when lower the equivalence ratio. Also,it shows that the acceleration effect of plasma on the flowfield evolution weakens with equivalence ratio decreases from the dynamic analysis of the thrust wall pressure,yet the magnitude of pressure is independent of the plasma. The reasons for the phenomenon that the lower equivalence ratio is not conducive to the plasma to play a role in expediting the DDT process under the lean burn condition are as follows: the disadvantage effect brought by the decline of the percentage of fuel is stronger than the effect of plasma assisted combustion,and the discharge area is limited.
引文
[1]中国科学院.中国学科发展战略[M].北京:科学出版社,2014.
[2]Starikovskiy A,Aleksandrov N.Plasma-Assisted Ignition and Combustion[J].Progress in Energy and Combustion Science,2013,39(1):61-110.
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[7]Ju Y,Sun W.Plasma Assisted Combustion:Dynamics and Chemistry[J].Progress in Energy and Combustion Science,2015,48:21-83.
[8]Takana H,Nishiyama H.Numerical Simulation of Nanosecond Pulsed DBD in Lean Methane-Air Mixture for Typical Conditions in Internal Engines[J].Plasma Sources Science and Technology,2014,23:034001.
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[13]Lefkowitz J K,Guo P,Ombrello T,et al.Schlieren Imaging and Pulsed Detonation Engine Test of Ignition by a Nanosecond Repetitively Pulsed Discharge[J].Combustion and Flame,2015,162:2496-2507.
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[15]郑殿峰,张义宁,郑日恒,等.交流驱动低温等离子体点火触发爆震可行性研究[J].推进技术,2014,35(8):1146-1152.(ZHENG Dian-feng,ZHANG Yining,ZHENG Ri-heng,et al.Investigation on Feasibility of Ignition and Detonation Trigger by Low Temperature Plasma Based on AC Drive[J].Journal of Propulsion Technology,2014,35(8):1146-1152.)
[16]Starikovskaya S M,Aleksandrov N L,Kosarev I N,et al.Ignition with Low-Temperature Plasma:Kinetic Mechanism and Experimental Verification[J].High Energy Chemistry,2009,43:213-218.
[17]Han J,Yamashita H.Numerical Study of Effect of NonEquilibrium Plasma on the Ignition Delay of a MethaneAir Mixture Using Detailed Ion Chemical Kinetics[J].Combustion and Flame,2014,161:2064-2072.
[18]Kosarev I N,Kindyshev S V,Momot R M,et al.Comparative Study of Nonequilibrium Plasma Generation and Plasma-Assisted Ignition for C2-Hydrocarbons[J].Combustion and Flame,2016,165:259-271.
[19]Tholin F,Lacoste D A,Bourdon A.Influence of FastHeating Processes and O Atom Production by a Nanosecond Spark Discharge on Ignition of a Lean H2-Air Premixed Flame[J].Combustion and Flame,2014,161:1235-1246.
[20]于锦禄,何立明,丁未,等.瞬态等离子体点火和火花塞点火起爆过程的对比研究[J].推进技术,2013,34(11):1575-1579.(YU Jin-lu,HE Li-ming,DING Wei,et al.Comparative Investigation on Detonation Initiation Process of Transient Plasma Ignition and Spark Ignition[J].Journal of Propulsion Technology,2013,34(11):1575-1579.)
[21]Zhou S,Nie W,Che X.Numerical Modeling of QuasiDC Plasma-Assisted Combustion for Flame Holding Cavity[J].Combustion Science and Technology,2016,188(10):1640-1654.
[22]Zhou S,Wang F,Che X,et al.Numerical Study of Nonequilibrium Plasma Assisted Detonation Initiation in Detonation Tube[J].Physics of Plasmas,2016,23(12):123522.
[23]Shih T H,Liou W W,Shabbir A,et al.A New k-εEddy-Viscosity Model for High Reynolds Number Turbulent Flows:Model Development and Validation[J].Computers Fluids,1995,24(3):227-238.
[24]熊姹,严传俊,邱华.不同化学反应机理对爆震波模拟的影响[J].燃烧学科与技术,2008,14(4):355-360.
[25]Zhou S,Nie W,Che X.Numerical Investigation of Influence of Quasi-DC Discharge Plasma on Fuel Jet in Scramjet Combustor[J].IEEE Transactions on Plasma Science,2015,43:896-905.
[26]兰宇丹,何立明,丁伟,等.不同初始温度下H2/O2混合物等离子体的演化[J].物理学报,2010,59(4):2617-2621.
[27]Starikovskiy A.Physics and Chemistry of Plasma-Assisted Combustion[J].Philosophical Transactions of the Royal Society A,2015,373:20150074.
[28]陈英.脉冲爆震发动机不同点火方式DDT过程模拟[D].南京:南京理工大学,2008.
[29]Mc Bride B J,Gordon S.Computer Program for Calculation of Complex Chemical Equilibrium Compositions and Applications[R].NASA 1996-1311-7.
[2]Starikovskiy A,Aleksandrov N.Plasma-Assisted Ignition and Combustion[J].Progress in Energy and Combustion Science,2013,39(1):61-110.
[3]Driscoll R,Stoddard W,George A St,et al.Shock Transfer and Shock-Initiated Detonation in a Dual Pulse Detonation Engine/Crossover System[J].AIAA Journal,2015,53(1):132-139.
[4]严传俊,范玮.脉冲爆震发动机原理及关键技术[M].西安:西北工业大学出版社,2005.
[5]赵炜,韩启祥,王家骅,等.热射流点火对多循环爆震管内火焰传播特性的影响[J].推进技术,2015,36(12):1846-1851.(ZHAO Wei,HAN Qi-xiang,WANG Jia-hua,et al.Effects of Hot Jet Ignition on Flame Propagation Characteristics in Multi-Cycle Detonation Tube[J].Journal of Propulsion Technology,2015,36(12):1846-1851.)
[6]陈星谷,王治武,郑龙席,等.预爆管布置方式对起爆特性影响的数值模拟研究[J].西北工业大学学报,2013,31(5):737-741.
[7]Ju Y,Sun W.Plasma Assisted Combustion:Dynamics and Chemistry[J].Progress in Energy and Combustion Science,2015,48:21-83.
[8]Takana H,Nishiyama H.Numerical Simulation of Nanosecond Pulsed DBD in Lean Methane-Air Mixture for Typical Conditions in Internal Engines[J].Plasma Sources Science and Technology,2014,23:034001.
[9]Zhukov V P,Starikovskii A Yu.Effect of a Nanosecond Gas Discharge on Deflagration to Detonation Transition[J].Combustion,Explosion,and Shock Waves,2006,42(2):195-204.
[10]Rakitin A E,Starikovskii A Yu.Mechanisms of Deflagration-to-Detonation Transition under Initiation by High-Voltage Nanosecond Discharges[J].Combustion and Flame,2008,155:343-355.
[11]Starikovskiy A,Starikovskiy N,Rakitin A.Plasma-Assisted Ignition and Deflagration-to-Detonation Transition[J].Philosophical Transactions of the Royal Society A,2012,370:740-773.
[12]Busby K,Corrigan J,Yu S,et al.Effects of Corona,Spark and Surface Discharges on Ignition Delay and Deflagration-to-Detonation Times in Pulsed Detonation Engines[R].AIAA 2007-1028.
[13]Lefkowitz J K,Guo P,Ombrello T,et al.Schlieren Imaging and Pulsed Detonation Engine Test of Ignition by a Nanosecond Repetitively Pulsed Discharge[J].Combustion and Flame,2015,162:2496-2507.
[14]Cathey C,Wang F,Tang T,et al.Transient Plasma Ignition for Delay Reduction in Pulse Detonation Engines[R].AIAA 2007-443.
[15]郑殿峰,张义宁,郑日恒,等.交流驱动低温等离子体点火触发爆震可行性研究[J].推进技术,2014,35(8):1146-1152.(ZHENG Dian-feng,ZHANG Yining,ZHENG Ri-heng,et al.Investigation on Feasibility of Ignition and Detonation Trigger by Low Temperature Plasma Based on AC Drive[J].Journal of Propulsion Technology,2014,35(8):1146-1152.)
[16]Starikovskaya S M,Aleksandrov N L,Kosarev I N,et al.Ignition with Low-Temperature Plasma:Kinetic Mechanism and Experimental Verification[J].High Energy Chemistry,2009,43:213-218.
[17]Han J,Yamashita H.Numerical Study of Effect of NonEquilibrium Plasma on the Ignition Delay of a MethaneAir Mixture Using Detailed Ion Chemical Kinetics[J].Combustion and Flame,2014,161:2064-2072.
[18]Kosarev I N,Kindyshev S V,Momot R M,et al.Comparative Study of Nonequilibrium Plasma Generation and Plasma-Assisted Ignition for C2-Hydrocarbons[J].Combustion and Flame,2016,165:259-271.
[19]Tholin F,Lacoste D A,Bourdon A.Influence of FastHeating Processes and O Atom Production by a Nanosecond Spark Discharge on Ignition of a Lean H2-Air Premixed Flame[J].Combustion and Flame,2014,161:1235-1246.
[20]于锦禄,何立明,丁未,等.瞬态等离子体点火和火花塞点火起爆过程的对比研究[J].推进技术,2013,34(11):1575-1579.(YU Jin-lu,HE Li-ming,DING Wei,et al.Comparative Investigation on Detonation Initiation Process of Transient Plasma Ignition and Spark Ignition[J].Journal of Propulsion Technology,2013,34(11):1575-1579.)
[21]Zhou S,Nie W,Che X.Numerical Modeling of QuasiDC Plasma-Assisted Combustion for Flame Holding Cavity[J].Combustion Science and Technology,2016,188(10):1640-1654.
[22]Zhou S,Wang F,Che X,et al.Numerical Study of Nonequilibrium Plasma Assisted Detonation Initiation in Detonation Tube[J].Physics of Plasmas,2016,23(12):123522.
[23]Shih T H,Liou W W,Shabbir A,et al.A New k-εEddy-Viscosity Model for High Reynolds Number Turbulent Flows:Model Development and Validation[J].Computers Fluids,1995,24(3):227-238.
[24]熊姹,严传俊,邱华.不同化学反应机理对爆震波模拟的影响[J].燃烧学科与技术,2008,14(4):355-360.
[25]Zhou S,Nie W,Che X.Numerical Investigation of Influence of Quasi-DC Discharge Plasma on Fuel Jet in Scramjet Combustor[J].IEEE Transactions on Plasma Science,2015,43:896-905.
[26]兰宇丹,何立明,丁伟,等.不同初始温度下H2/O2混合物等离子体的演化[J].物理学报,2010,59(4):2617-2621.
[27]Starikovskiy A.Physics and Chemistry of Plasma-Assisted Combustion[J].Philosophical Transactions of the Royal Society A,2015,373:20150074.
[28]陈英.脉冲爆震发动机不同点火方式DDT过程模拟[D].南京:南京理工大学,2008.
[29]Mc Bride B J,Gordon S.Computer Program for Calculation of Complex Chemical Equilibrium Compositions and Applications[R].NASA 1996-1311-7.