2D阀先导级气穴特性的可视化实验

Visualization Experiment on Cavitation Characteristics of Pilot Stage of Two-dimensional Valve

二维(2D)阀的阀芯具有周向转动和轴向移动的2个自由度,可实现先导控制和功率放大。其先导级阀口因节流会产生气穴,引起阀芯振动并伴有噪声,直接影响阀的稳定性。为研究2D阀先导级处气穴现象及其影响因素,开发了一套可视化实验装置,结合两相流仿真研究,验证了气穴现象与阀口开度、敏感腔体积、节流口形状、入口压力关系密切。结果表明:2D阀先导级高压节流口处的气体体积随阀口开度的增加而减少,直至消失;随入口压力增加,气体体积的变化近似呈线性增长趋势;随着敏感腔体积的增大而显著增加,平均增长速度达62%,且气体分布变得不规则;矩形节流口比弓形节流口处的气穴受入口压力等因素的影响较大,弓形节流口在入口压力增加时,气体体积增量仅为矩形的8%;同时发现,随着气体在感受通道内的扩散,气体边界从最初的类矩形变成多段不规则形状。

The valve core of two-dimensional(2D)valve has the two degrees of freedom of functions of circumferential rotation and axial movement,enabling pilot control and power amplification.The cavitation due to throttle generated by the pilot stage valve orifice will cause vibration and noise of the valve core,which directly affects the stability of the valve.In order to study the cavitation phenomenon at the pilot stage of the 2D valve and its influencing factors,designed a visualization experimental device,and combined with two-phase flow simulation studies to verify that the cavitation phenomenon is closely related to the valve orifice opening,sensitive cavity volume,throttle orifice shape and inlet pressure.The results show that the gas volume at the high-pressure throttle orifice of the pilot stage of the 2D valve decreases with the increase of the valve opening until it disappears;The change of gas volume is approximately linear increase trend with increasing inlet pressure;The gas volume is also increasing significantly as the volume of the sensitive cavity increases,with an average growth rate of 62%,and the gas distribution becomes irregular;The gas volume at the rectangular throttle orifice is more affected by factors such as inlet pressure than at the bowed throttle orifice,when the inlet pressure of the bow throttle orifice increase,the gas volume only increases by 8%of that of the rectangle throttle orifice;It was also observed that the gas boundary changed from an initial rectangular-like shape to a multi-segmented irregular shape as the gas diffused within the sensing channel.