CAJ | 학술논문

采用三维CFD模型模拟了直喷柴油机缸内喷雾燃烧过程,模拟缸压曲线得到了实验的验证.通过高温区与喷嘴之间的稳定距离来确定柴油机火焰浮起长度,研究在不同进气条件下火焰浮起长度的变化情况.该模型成功地预测了火焰浮起长度随着初始进气压力的增大而减少,随着进气温度的升高出现先增大后减少的趋势.同时模拟了在不同EGR率下柴油机缸内燃烧情况,发现火焰浮起长度和燃料着火延迟时间都随EGR率的增加而增大.
채용삼유CFD모형모의료직분시유궤항내분무연소과정,모의항압곡선득도료실험적험증.통과고온구여분취지간적은정거리래학정시유궤화염부기장도,연구재불동진기조건하화염부기장도적변화정황.해모형성공지예측료화염부기장도수착초시진기압력적증대이감소,수착진기온도적승고출현선증대후감소적추세.동시모의료재불동EGR솔하시유궤항내연소정황,발현화염부기장도화연료착화연지시간도수EGR솔적증가이증대.
The spray and combustion processes in a DI diesel engine are simulated with a multi-dimensional CFD model,and the simulated in-cylinder pressure is in good agreement with the measured one.The flame lift-off length is determined with the stabilized distance between the high temperature zone and the nozzle exit,and the influences of different intake gas conditions on the flame lift-off length are investigated.With the CFD model we successfully predict that the flame lift-off length tends to decrease as the initial intake gas pressure is increased.With an increase in the intake gas temperature.the flame lift-off length presents a tendency to increase first and decrease afterwards.The model is also applied to simulate the combustion process in the diesel engine in different EGR rate conditions.and the computed results show that both the flame lift-off length and the auto-ignition delay time are increased with increase in EGR rate.