螺旋进气道气门口处流速分布的研究

A Study on Steady Flow Velocity Distribution Around the Valve Seat of Helical Port

本文应用热线风速仪测定了螺旋进气道气门出口处的气流速度,从几种不同型式气道的试验与分析中得知,气门出口处切向气流速度产生的绕气缸轴线的动量矩流率约占气缸内总动量矩流率的60%以上,这说明气缸内的涡流主要是由气门口切向速度产生的。螺旋进气道气门口周边上存在着正动量矩流率区与负动量矩流率区,负动量矩流率主要由气门出口处气流的径向速度产生,它对进气涡流起削弱作用。进气门口周边存在主要出气区,气道的阻力由流通速度和流通系数共同决定。根据这些认识,作者对6110A 柴油机的螺旋进气道进行改进设计,取得了较好的结果。

In this paper,a hot-wire anemometer is used for obtaining theair flow velocity distribution around the value seat annulus of helical port.It is foundfrom the experiment and analysis of several different types of helical ports that the ang-ular momentum flux around cylinder axis produced by tangential velocity at intakevalve seat annulus accounts for about 60% of the total angular momentum flux.Thismeans that the swirl in cylinder is mainly produced by tangential velocity at valve seatannulus;It is also found that a positive and a negative angular momentum flux regionsexist around the valve seat.The negative angular momentum flux which plays a red-uctive role to the intake swirl is mainly produced by the radial air flow velocity aroundthe valve seat annulus.There is a main air outflow region around the valve seat annulus.The air flow resistance of the port is determined by flow velocity and flow coefficientaround the intake valve.According to above recognitions,the design of helical port for 6110A diesel enginehas been improved and good results have been obtained.