滑移速度对织构表面气穴效应的影响

为研究不同的滑移速度对织构表面气穴效应的影响,建立单个微凸体织构的二维计算模型,利用CFD方法模拟不同滑移速度下气穴效应在气体体积率、压力分布和壁面剪切力等方面的表现。研究结果表明:当滑移速度不超过5 m/s时,织构表面的流体中不产生气穴;当滑移速度由5 m/s逐渐增大到20 m/s时,在织构流体出口端的收敛区将生成气穴,气穴的大小随着滑移速度的增大而减小,气穴处的气体体积率随着滑移速度的增大而增加;当滑移速度继续由20 m/s增大至30 m/s之间的某值以后,气穴的大小不再减小,气体的体积率仍随滑移速度的增大而增加。滑移速度在5~30 m/s的范围内,滑移速度越大,产生的额外承载力越大,壁面剪切力越大。此外,气穴的存在有助于降低壁面剪切力。

The Influence of Slip Velocity on the Cavitation Effect of Surface Texture

In order to study the influence of slip velocity on the cavitation effect of texture surface,a single two-dimensional calculation model of micro convex body texture was established.Using the method of CFD simulation,as the change of sliding velocity,the changing rules of the cavitation effect in gas volume rate,pressure distribution and wall shear stress were obtained.The results show that when sliding speed is not more than 5 m/s,any cavitations can not be produced on the texture surface of the fluid;when the slip velocity gradually increases from 5 m/s to 20 m/s,cavitations will be generated in the convergence area of texture fluid outlet,and the size of the cavitations will be decreased with the increase of the slip velocity,and the gas volume rate of the cavitations will be increased with the increase of the slip velocity;when the slip velocity continues to increase from 20 m/s to 30 m/s and reaches a certain value,the size of the cavitations will be decreased no longer,and the gas volume rate of the cavitations still increases with the increase of the slip velocity;when the slip velocity is between 5 m/s to 30 m/s,the greater slip velocity will be corresponding to the greater extra capacity and the greater wall shear stress.In addition,the existence of cavitations will contribute to reduce the wall shear stress.