二甲基醚燃烧过程及其优化的数学模拟(Ⅰ)——燃烧模型

Investigation on Mathematical Model and Optimizing of Combustion Process for DME (1)—Combustion Model

在定容燃烧弹实验和发动机台架实验基础上建立了二甲基醚 DME燃烧过程的准维多区的现象学燃烧模型 ,模型针对 DME燃烧过程的特点 ,建立了新的喷雾混合和着火滞燃期子模型 ,修正了燃烧放热率子模型 ,研究了DME燃烧过程中氮氧化物 (NOx)生成机理。模型的计算结果和实验结果相当吻合 ,模型对变工况、变参数有较好的适应能力。NOx 生成历程计算分析表明 ,DME燃烧过程中 NOx 主要在扩散燃烧阶段生成 ,燃烧温度低是 NOx

In recent years,the study of dimethyl ether (DME) as an alternative fuel for diesel engine has been vigorously carried out all over the world.Compared with the conventional diesel fuel,the engine operated with DME demonstrated the potential for low NO x emissions,low engine noise,and smoke free.Therefore,DME is a very attractive and hopeful alternative fuel for diesel engines.In this paper a quasi dimensional multi zone combustion model for DME has been developed,including a new spray mixing sub mode,a new ignition delay sub mode and a new heat release sub mode based on the experimental study on DME spray characteristics and DME combustion processes.It is found that the calculated results agree very well with the test data,and this mode has strong adaptability to the variable mode and variable parameters.With this mode,the NO x formation mechanism of the DME has been investigated.The results show that NO x formation mainly occurs in the diffuse combustion phase,and the low NO x emissions are due to the low combustion temperature.