二甲醚发动机湍流燃烧模型的研究(英文)

Study on a Turbulent Combustion Model of DME Engine

根据二甲醚发动机燃烧过程的特点,提出一种湍流燃烧模型。该模型在传统化学动力学模型的基础上,增加了拟序火焰片湍流燃烧模型以考虑湍流对燃烧的促进作用。数值模拟表明,二甲醚在发动机中油束贯穿度比柴油短;油孔附近的油束上边缘处具有合适的燃料浓度和较高温度,最先发生自燃;在扩散燃烧时燃料与空气混合速度慢,燃烧速度慢,持续时间长。计算结果与试验观察基本相符。

A turbulent combustion model was developed to study the combustion characteristics of DME engine.The coherent flamelet sub-model was added into the traditional chemical kinetic model to take into account of turbulent influence.Simulation results indicated that DME spray had shorter tip penetration than that of diesel fuel.The upper edge of spray near the nozzle has the appropriate fuel concentration and relative high temperature where is first to ignite fuel.In diffusion burn stage the combustion rate is slow and lasts a long period due to slow air-fuel mixture formation.The calculated results have a good agreement with those of experimental observation.