甲醇/二甲醚RCCI发动机燃烧性能数值研究

Numerical Study on Combustion Characteristics of A Methanol/Dimethyl Ether Reactivity Controlled Compression Ignition(RCCI)Engine

以甲醇和二甲醚分别为低、高反应活性燃料,甲醇能量比例和喷油时刻为变量,数值模拟了低负荷工况下反应活性控制压燃(RCCI)和逆向反应活性控制压燃(R-RCCI)发动机的性能,并对两种燃烧方式进行了对比。仿真结果表明:在本文的研究工况下,RCCI燃烧放热速率快、缸压峰值高,而R-RCCI高温氧化放热时刻早、放热速率平缓、燃烧持续期长。相较于RCCI燃烧,R-RCCI燃烧的燃烧相位可灵活调节,等效指示燃油消耗率可达164.5 g/kWh,而且允许的甲醇能量比例和喷油时刻范围更广。

Taking the methanol energy ratio and injection time as variables,the performance of reactivity controlled compression ignition(RCCI)and RCCI with reverse reactivity stratification(R-RCCI)fueled methanol and dimethyl ether under low load conditions was numerically simulated and the two combustion methods were compared.The simulation results show that under the research conditions in this paper,RCCI has a fast combustion and release rate and high peak cylinder pressure,while R-RCCI has a gentle heat release rate and a long combustion duration.Compared to RCCI combustion,the combustion phase of R-RCCI combustion can be flexibly adjusted,EISFC can reach 164.5 g/kWh,and the allowable methanol energy ratio and injection time range is wider.