基于米勒循环发动机的缸内流动优化

Optimization of In-cylinder Flow Based on Miller Cycle Engine

采用三维计算流体力学软件STAR-CD对某米勒循环发动机进行数值模拟计算,分析进气道喉口附近截面积、燃烧室进气鼻梁区气门遮蔽以及活塞顶凸台高度和凹坑直径对米勒循环发动机缸内瞬态滚流比和湍动能的影响。结果表明:优化进气道喉口附近截面积、燃烧室进气鼻梁区气门遮蔽以及活塞顶凸台高度和凹坑直径能够提高缸内滚流比和湍动能,3种优化方案对缸内流动改善的效果顺序依次为进气道、活塞和燃烧室。

The three-dimensional computational fluid dynamics software, STAR-CD, is used to carry out the numerical simulation of a miller＇s circle engine, and analyze the influence of the sectional area near the inlet throat, the valve occlusion in the inlet nose area of the combustor and the height of the piston head and the crater diameter on the transient roll ratio and turbulent kinetic energy in the miller＇s circle engine. The results show that the flow ratio and turbulent kinetic energy in the cylinder can be improved by optimizing the cross- sectional area near the inlet throat, the valve occlusion of the inlet nose area of the combustion chamber and the height of the piston head and the pit diameter, and the effect of three optimization schemes on the improvement in the cylinder is in order of inlet, piston and combustion chamber.