HCCI汽油机燃烧和排放特性的仿真分析

Numerical Simulation Analysis on Combustion and Emission of HCCI Gasoline Engine

研究内燃机燃烧特性问题,为了能更为准确地预测HCCI汽油机缸内燃烧特性和排放特性,提出建立了内燃机缸内工作过程的动网格模型,并对狭缝进行加密。对汽油均质压缩燃烧发动机的燃烧过程和排放物的生成过程进行了仿真分析。利用Fluent软件耦合详细化学反应机理,采用RNG k-ε模型以及化学反应涡耗散概念(EDC)模型,计算了特定条件下缸内的温度与压力的变化过程以及缸内的燃料及碳烟等变化趋势,结果表明:狭缝是产生CO和碳氢化合物的主要来源,在详细化学反应机理基础上应用RNG k-ε和化学反应EDC模型能够较为准确地预测HCCI汽油机缸内燃烧和排放。仿真为实际的设计提供了依据。

In this paper,in order to accurately predict the combustion and emission characters of HCCI gasoline engine by building dynamic mesh model and encrypting slit flter,we calculated the process of combustion and emissions forming in a HCCI gasoline engine by using CFD software FLUENT coupled with detailed chemical kinetic mechanism and choosing RNG k-ε and EDC model.The pressure contours,the temperature contours,the changes of fuel and the soot are simulated at a given condition.The simulation results are in good agreement with the experimental data.The analysis of simulation showed that the slit fliter is the main source of HC and CO emission.In addition,The results of this study prove that this method is a very potential tool for the design and research of the HCCI gasoline engine and is a useful guide for combustion optimization of HCCI engineby using RNG k-ε and EDC model based on detailed chemical kinetic mechanism.