摘要
为研究缸内气流运动规律,探索燃烧室形状对挤流的影响,在柴油机的压缩和膨胀工况下,应用STAR CD程序对不同几何形状的燃烧室内气流运动进行三维数值模拟。计算结果表明,缩口燃烧室具有较大的挤流强度,较长的涡流持续期,涡流的分布较合理,有利于混合气的形成,可加速扩散燃烧;直口燃烧室性能相对较弱;敞口燃烧室性能最弱。燃烧室的收口程度和底部凸台的形状是影响挤流的两个重要因素。燃烧室偏心造成缸内流场的不对称,影响了混合气的形成,不利于燃烧。
In order to investigate the rule of air flow moving in the cylinder, and the affection of combustion chamber shape on the squish, the air motion in four different geometrical combustion chambers(A,B,C,D) was calculated using STAR-CD under the condition of compress and expansion stroke. The results show that the shape of chamber plays an important role to in-cy linder air flow. The contracted open cave (chamber A) has much strong squish lasting long-term period and distributing reasonably, which is favor to formation of the mixture. The diffuse combustion could be enhanced, which demonstrates chamber A has the best performance. The engine performance with chamber B is relatively worse, and chamber C is the worst. The size of chamber throat and the shape of the convexity are keys to form reasonable squish. In chamber D, which geometrical center offsets from cylinder axis, the air flow field in the cylinder is not symmetrical. So it is unbeneficial to form homogeneous fuel-air mixture, resulting in rough combustion.
出处
《车用发动机》
北大核心
2005年第3期8-12,共5页
Vehicle Engine
基金
国家重点基础研究发展规划资助项目(2001CB209202)
关键词
柴油机
燃烧室
数值模拟
流场
diesel engine
combustion chamber
numerical simulation
flow field
