准维模型中若干参数对建模精度的影响分析

Analyzing on Precision of Some Parameters in Quasi Dimensional Combustion Model Constructing

现象学燃烧模型是一种准维模型。由于进行了分区处理并考虑了较多与燃烧过程有关的因素，所以可在一定程度上预测排放。但其预测结果精度受到诸多参数的影响。本文在将它应用到有较强进气涡流的小缸径高速直喷式柴油机上时特别计及了进气涡流强度对各区之间质量传递的影响，在模型构建中，摸清了若干燃烧组织的重要参数对模型预测结果精度的影响。本文分别讨论了这些参数对输出结果的影响，并将部分计算结果与实测结果进行了对比。结果表明：各参数的影响不一，其中掺混系数β由于对传质量影响较大，从而影响各区内的温度而对氮氧化物预测精度的影响最大。因此，提高模型预测精度的关键是正确选取各参数值。

Phenomenological combustion model is a kind of quasi dimensional combustion model.As the volume in cylinder is divided into 4 zones the model can be used to predicate the performance and pollution level of D.I.diesel engines.As the precision of predicted results are strongly influenced by some parameters,this paper presents an investigation to make clear the influence between calculated results and measured ones.Also the influence of swirl ratio on mass transmission is considered.Some comparison are made between calculated results and measured ones.Research results demonstrate that the coefficient β ,as it influences the mass transmission and the temperature among the zones,has a stronger influence on predicted results.Key to get accurate deduced results in constructing the model is to choose reasonable value of the parameters.