内流式滑阀壁面压力分布可视化计算及试验验证

Visualization Calculation and Experimental Verification of Steady Axial Flow Force on the Converged Flow Sliding Valve

针对现有液压阀流场(Computational fluid dynamics,CFD)仿真研究中,采用单相流模型进行计算,忽略了流体气化现象对流体密度及其流场的影响,仿真所得相对压力过低与实际不符的问题,运用Fluent软件,采用两相流模型,研究内流式滑阀流场分布,分析阀口开度、流量变化对于阀芯壁面压力分布及其稳态液动力的影响;设计一种壁面压力分布测量的试验方案,测量得到阀芯壁面的压力分布,并通过表面积积分法求出阀芯所受稳态液动力。结果表明:试验所得的内流式滑阀的壁面压力分布及其稳态液动力与仿真结果趋势一致,壁面压力峰值随着阀口开度的增大而减小;阀口开度较小时,稳态液动力的方向为阀口关闭的方向,在阀口开度达到临界点时,稳态液动力的方向为阀口打开的方向;滑阀稳态液动力公式计算由于忽略了入口射流角的变化及其出口处的动量,得到的稳态液动力误差较大,且方向始终指向阀口打开的方向。

In view of the existing problem which does not accord with the fact, that is, in the hydraulic valve flow field CFD study, the single-phase flow model ignores the influence on fluid density and fluid flow field under the condition of cavitation occurred, which leads to the result of the lower relative pressure, by using Fluent software and multiphase model, field distribution is studied on the converged flow sliding valve,and the influence by the change in the flow rate and valve orifice is analyzed on the spool wall pressure distribution and the steady-state flow force. A measurement scheme of wall pressure distribution is designed. The surface integral of the measurement value is the steady flow force. The result is the experimental data is consistent with the simulation＇s, and the peak of the wall pressure distribution decreases with the increasing of the orifice area. the orifice area is smaller, the direction of the steady flow force is the direction of the orifice closing. when the orifice area reaches a critical value, its direction is the direction of the orifice opening. the formula of the steady flow force on the slide valve omits the changes of the flow angle at the orifice and the momentum at the exit, so it makes the bigger error for the steady flow force, the direction of steady flow force always points to the direction of the valve orifice opening.