摘要
基于计算流体力学(CFD)程序耦合动力学机理,研究了一台大型低速二冲程船用柴油机改装的柴油-天然气双燃料发动机预燃室系统的布置方案对射流火焰发展过程的影响,以及由此对缸内流动、燃烧和有害污染物氮氧化物(NO_x)生成历程的影响。结果表明:预燃室方案造成射流火焰对撞会对碰撞区域及周围流场产生较大扰动,同时在碰撞区域形成富燃区,抑制该区域内NO_x的生成;射流火焰不碰撞则会增大其贯穿距离,实现更大空间范围的多点着火,放热更集中,同时会因较高的温度使NO_x排放上升;此外射流火焰与缸盖、活塞和缸套等壁面接触会显著降低其流动速度和燃烧温度,造成燃烧效率下降,缸内湍动能减小,在实际应用中应尽可能避免。
In order to research the effect of pre-chamber system to development of flame jet,in-cylinder flow,combustion process and generation of emission,based on Computational Fluid Dynamics(CFD)program and chemical reaction kinetics,this paper built a numerical model of a large low-speed dual fuel marine engine modified by a normal diesel marine engine and explored the effect of different position cases of pre-chamber.The results show:When pre-chamber case cause flame jet collide,the flow field of colliding area is disturbed strongly,it also takes fuel-rich mixed gas to this area,which restrains the generation of oxynitride(NO x);If there is no collision between jet-flame,the flame jet penetration will be longer and combustion achieve wider-region multi-spot ignition in cylinder,which make heat release more focused,however it also brings higher level NO x emission.Besides,contact with wall such as cylinder head,liner,piston crown,will reduce the rate of jet flow observably.It also leadstoreducing of combustion temperatureandturbulentkinetic energyin cylinder,even causes combustion deterioration,which should be avoid.
作者
叶映
董晶瑾
王浒
刘腾
刘海峰
尧命发
YE Ying;DONG Jingjin;WANG Hu;LIU Teng;LIU Haifeng;YAO Mingfa(State Key Laboratory of Engine Combustion,Tianjin University,Tianjin 300072,China;China Shipbuilding Power Engineering Institute,Shanghai 200120,China)
出处
《内燃机工程》
EI
CAS
CSCD
北大核心
2018年第2期22-28,34,共8页
Chinese Internal Combustion Engine Engineering
基金
工信部高技术船舶科研项目(CDGC01-KT0308)~~
关键词
低速船机
双燃料
预燃室
射流火焰
low-speed marine engine
dual fuel
pre-chamber
flame jet
