组喷孔喷嘴对双对置柴油机喷雾及燃烧的影响
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摘要
针对双对置柴油机混合气形成困难的特点,采用CONVERGE CFD软件,建立双对置柴油机数值仿真模型。设计3种汇聚型组喷孔喷嘴的喷孔布置方案,研究在保持喷油压力不变的前提下,对3种方案下喷雾、混合气形成和燃烧过程进行分析。结果表明:与传统喷嘴相比,改进后的组喷孔喷嘴对喷雾贯穿距影响较小,有利于缸内湍流动能的提高,加快缸内混合气的形成速率。同时,组喷孔喷嘴使燃油分布更加均匀,分布区域也更广,有利于改善油气混合质量,提高双对置发动机气缸压力和燃烧效率,达到提升双对置发动机性能的效果。其中,第3种组喷孔布置方案下发动机指示功率可提高7.6%。
With focus on the difficulty of mixture formation of an opposed piston opposed cylinder diesel engine,CONVEGE CFD software was employed to establish the numerical simulation model of an opposed piston opposed cylinder diesel engine.Three arrangements of the converging group-hole nozzle were designed,and without modifying the injection pressure,the fuel spray,mixture formation and combustion process of an opposed piston opposed cylinder diesel engine model were analyzed.The results indicated that the grouphole nozzle had negligible influences on spray penetration distance compared with conventional nozzle.The group-hole nozzle was helpful in improving the in-cylinder turbulence kinetic energy and accelerating the air-fuel mixing rate.Meanwhile,the mixture was evenly distrib-uted and widely spread,helping to improve the quality of mixture and increase the in-cylinder pressure and combustion efficiency as well as improve the engine performance.Among three designs,the indicated power of the engine with the third pattern of converging group-hole increased by 7.6%.
With focus on the difficulty of mixture formation of an opposed piston opposed cylinder diesel engine,CONVEGE CFD software was employed to establish the numerical simulation model of an opposed piston opposed cylinder diesel engine.Three arrangements of the converging group-hole nozzle were designed,and without modifying the injection pressure,the fuel spray,mixture formation and combustion process of an opposed piston opposed cylinder diesel engine model were analyzed.The results indicated that the grouphole nozzle had negligible influences on spray penetration distance compared with conventional nozzle.The group-hole nozzle was helpful in improving the in-cylinder turbulence kinetic energy and accelerating the air-fuel mixing rate.Meanwhile,the mixture was evenly distrib-uted and widely spread,helping to improve the quality of mixture and increase the in-cylinder pressure and combustion efficiency as well as improve the engine performance.Among three designs,the indicated power of the engine with the third pattern of converging group-hole increased by 7.6%.
引文
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[10] NISHIDA K,ZHANG W,MANABE T.Effects of microhole and ultra-high injection pressure on mixture properties of DI diesel spray[R].SAE Technical Paper 2007-01-1890,2007.
[11]张扬,谢侃,岳明辉,等.流体喉部横流喷嘴的雾化特性[J].航空动力学报,2017,32(5):1074-1081.ZHANG Yang,XIE Kan,YUE Minghui,et al.Atomization characteristics of cross-flow injector in the fluidic nozzle throat[J].Journal of Aerospace Power,2017,32(5):1074-1081.(in Chinese)
[12] ZHANG Y,NISHIDA K,NOMURA S,et al.Spray characteristics of a group-hole nozzle for direct-injection diesel engines[J].Atomization and Sprays,2006,16(1):35-50.
[13] KIM S,NAMBA M,SHIMO D,et al.Numerical analysis of the mechanism in diesel mixture formation and emission reduction by group hole nozzle[C]∥The 20th Internal Combustion Engine Symposium.Tokyo:The Japan Society of Mechanical Engineers,2009:1-3.
[14] PARK S,REITZ R D,KIM J.Combustion and emission characteristics of converging group-hole nozzle under lean engine operating conditions[J].Fuel,2011,90(11):3259-3267.
[15] KIM J,PARK S W,ANDRIE M,et al.Experimental investigation of intake condition and group-hole nozzle effects on fuel economy and combustion noise for stoichiometric diesel combustion in an HSDI diesel engine[J].SAE International Journal of Engines,2009,2(1):1054-1067.
[16]齐文亮,明平剑,张文平,等.不同液滴破碎模型的验证及柴油机在燃气混合过程中的应用[J].航空动力学报,2018,33(9):2093-2100.QING Wenliang,MING Pingjian,ZHANG Wenping,et al.Evaluation of different breakup models and application to the mixture preparation process for diesel[J].Journal of Aerospace Power,2018,33(9):2093-2100.(in Chinese)
[17] JIAN G,MATSUMOTO Y,NISHIDA K.Effects of grouphole nozzle specifications on fuel atomization and evaporation of direct injection diesel sprays[R].SAE Technical Paper 2007-01-1889,2007.
[18] MOON S,MATSUMOTO Y,NISHIDA K,et al.Improving diesel mixture preparation by optimization of orifice arrangements in a group-hole nozzle[J].International Journal of Engine Research,2010,11(2):109-126.
[2] KALKSTEIN J,RVER W,CAMPBELL B,et al.Opposed piston opposed cylinder(OPOCTM)5/10kW heavy fuel engine for UAVs and APUs[R].SAE Technical Paper2006-01-0278,2006.
[3] HOFBAUER P.Opposed piston opposed cylinder(OPOC)engine for military ground vehicles[R].SAE Technical Paper 2005-12-1548,2005.
[4] FLINT M,PIRAULT J P.Opposed piston engines:evolution,use,and future[M].Detroit,US:SAE,2009:456-458.
[5]谢钊毅.对置活塞二冲程柴油机喷雾过程的试验研究与数值模拟[D].北京:北京理工大学,2016.XIE Zhaoyi.Experimental study and numerical simulation of the spray process in an opposed-piston two-stroke diesel engine[D].Beijing:Beijing Institute of Technology,2016.(in Chinese)
[6]强永平,李耀宗,白洪林,等.组合喷射对双对置二冲程发动机燃烧过程影响的计算研究[J].车用发动机,2014(5):46-53.QIANG Yongping,LI Yaozong,BAI Honglin,et al.Influence of combined injection on OPOC two-stroke engine combustion[J].Vehicle Engine,2014(5):46-53.(in Chinese)
[7]杨峰.双对置柴油机侧向组合喷雾-燃烧过程的数值模拟研究[D].长沙:湖南大学,2016.YANG Feng.Numerical simulation on lateral combined spray and combustion of dual opposed diesel engine[D].Changsha:Hunan University,2016.(in Chinese)
[8]刘军萍.高功率密度OPOC柴油机喷雾燃烧过程与喷油策略研究[D].太原:中北大学,2013.LIU Junping.Research on spray-combustion process and injection methods of high power density diesel engine[D].Taiyuan:North University of China,2013.(in Chinese)
[9] BERGSTRAND P,FRSTH M,DENBRATT I.The influence of orifice diameter on flame lift-off length[R].Zaragoza,Spain:ILSS-Europe Annual Conference,2002.
[10] NISHIDA K,ZHANG W,MANABE T.Effects of microhole and ultra-high injection pressure on mixture properties of DI diesel spray[R].SAE Technical Paper 2007-01-1890,2007.
[11]张扬,谢侃,岳明辉,等.流体喉部横流喷嘴的雾化特性[J].航空动力学报,2017,32(5):1074-1081.ZHANG Yang,XIE Kan,YUE Minghui,et al.Atomization characteristics of cross-flow injector in the fluidic nozzle throat[J].Journal of Aerospace Power,2017,32(5):1074-1081.(in Chinese)
[12] ZHANG Y,NISHIDA K,NOMURA S,et al.Spray characteristics of a group-hole nozzle for direct-injection diesel engines[J].Atomization and Sprays,2006,16(1):35-50.
[13] KIM S,NAMBA M,SHIMO D,et al.Numerical analysis of the mechanism in diesel mixture formation and emission reduction by group hole nozzle[C]∥The 20th Internal Combustion Engine Symposium.Tokyo:The Japan Society of Mechanical Engineers,2009:1-3.
[14] PARK S,REITZ R D,KIM J.Combustion and emission characteristics of converging group-hole nozzle under lean engine operating conditions[J].Fuel,2011,90(11):3259-3267.
[15] KIM J,PARK S W,ANDRIE M,et al.Experimental investigation of intake condition and group-hole nozzle effects on fuel economy and combustion noise for stoichiometric diesel combustion in an HSDI diesel engine[J].SAE International Journal of Engines,2009,2(1):1054-1067.
[16]齐文亮,明平剑,张文平,等.不同液滴破碎模型的验证及柴油机在燃气混合过程中的应用[J].航空动力学报,2018,33(9):2093-2100.QING Wenliang,MING Pingjian,ZHANG Wenping,et al.Evaluation of different breakup models and application to the mixture preparation process for diesel[J].Journal of Aerospace Power,2018,33(9):2093-2100.(in Chinese)
[17] JIAN G,MATSUMOTO Y,NISHIDA K.Effects of grouphole nozzle specifications on fuel atomization and evaporation of direct injection diesel sprays[R].SAE Technical Paper 2007-01-1889,2007.
[18] MOON S,MATSUMOTO Y,NISHIDA K,et al.Improving diesel mixture preparation by optimization of orifice arrangements in a group-hole nozzle[J].International Journal of Engine Research,2010,11(2):109-126.