适用于低温条件下的双燃料发动机燃烧机理研究与应用

Research and application of dual fuel engine combustion mechanism suitable for low temperature condition

本文研究和建立一种包括172个组分、818步反应、适用于低温条件下的双燃料简化机理模型,用来预测双燃料发动机的燃烧和排放特性。机理模型针对点火延迟、层流火焰速度进行了验证,结果表明本文建立的简化机理模型可靠。最后,将本文简化的柴油/天然气双燃料机理模型耦合到CFD软件中,研究不同LNG替代率(0、30%、60%、90%)下双燃料发动机的燃烧特性和排放。结果表明:随着LNG替代率的增加,缸内的最高燃烧温度和最大爆发压力降低,进而减少了NOX和SOOT的排放,但是CO和CH_(4)的排放增多。

In this paper, we study and establish a dual-fuel simplified mechanism model suitable for low-temperature conditions, including 172 components and 818-step reactions to predict the combustion characteristics and emissions of dualfuel engines. The final optimized mechanism model is verified for ignition delay and laminar flame velocity, and the results show that the simplified mechanism model established in this paper is reliable. Finally, the simplified diesel/natural gas dualfuel mechanism model in this paper is coupled to CFD software to simulate and calculate the combustion characteristics and emissions of dual-fuel engines at different LNG substitution rates(0, 30%, 60%, 90%). The results show that as the LNG replacement rate increases, the maximum combustion temperature and maximum explosion pressure in the cylinder decrease,thereby reducing NOX and SOOT emissions, but CO and CH_(4) emissions will increase.