论文部分内容阅读
通过对 K10 0二冲程汽油机倒拖工况下扫排气道 -缸内系统流场的三维瞬态数值模拟 ,发现整个扫气阶段的缸内流场是由三维回流组成的。主扫气口径向平面的切向倾斜角偏小 ,径向汇聚角偏大 ,产生了明显的短路损失 ,并在缸盖顶局部产生了反向流动形成的“死角”。为此 ,调整了主扫气口的扫气角 ,其它参数均不改变。计算结果表明 :缸内分层扫气十分清晰 ,短路损失及死角明显减少 ,反向流动被消除。但缸内回流 -环涡的流动结构基本不变
Through the three-dimensional transient numerical simulation of the flow field in the sweeping exhaust-in-cylinder system of K10 0 two-stroke gasoline engine, it was found that the in-cylinder flow field in the entire scavenging stage is composed of three-dimensional backflow. The tangential tilt angle of the main scoop radial plane is small, the radial convergence angle is too large, resulting in significant short-circuit loss and a “dead corner” formed at the top of the cylinder dome by reverse flow. For this reason, the scavenging angle of the main scavenging air port is adjusted, and other parameters are not changed. The calculation results show that the stratified scavenging in the cylinder is very clear, the short-circuit loss and dead angle are obviously reduced, and the reverse flow is eliminated. However, the flow structure of the in-cylinder return-ring vortex is basically unchanged