直喷式柴油发动机主要污染物的仿真及实验

Simulation and Experiment for Main Pollutions in Direct-injection Diesel Engine

为计算直喷式柴油机的主要污染物———碳烟和氮氧化物,提出了R IF计算模型。此小火焰计算模型是通过引入理想混和比分数空间坐标系,将通常坐标系下的组元方程转化到混和比分数空间坐标系下,得出新的组元扩散方程。同时将小火焰计算模型与对流体动力学程序(KIVA-3V)相结合,增加并修改原有计算模块,将湍流喷雾运动和湍流燃烧运动有机分开,计算出直喷式柴油机湍流燃烧后生成的碳烟和氮氧化物,最后通过实验检验了该计算模型。

The representative interactive flamelet （R IF） model is presented and used for 3 -D simulation pollution （soot and NOx） for direct -injection diesel engine. The model is based on stoichiometric mixture fraction space, and a way of separating the numerical effort associated with the solution of the turbulent flow field from that of solving the chemistry is offered. The new species and temperature equations are carried out. The results from the species equation are developed and the probability density function （PDF） with the mixture fraction is got. Then the probability density function is put into the CFD -code （KIVA -3V） and the CFD -code （KIVA -3V） is modified for the RIF model. Furthermore, the soot and NOx are calculated and compared with the experimental data. It gives a new way to predict the pollutants for direct -injection diesel engine.