圆形Rayleigh台阶腔体流动特性的数值模拟

Numerical simulation on flow characteristics of round Rayleigh step cavity

为了揭示流体流动特性对静压支承油腔承载力的影响,根据圆形Rayleigh台阶腔体流动特性,将流动分为三部分:入口中心对称碰撞流动、凹槽径向发散流动和节流边微流动.采用计算流体力学(CFD)方法建立计算模型,对腔体几何参数(e,h)和入口雷诺数(Re)等因素对流场涡胞的影响进行数值模拟.结果表明:Rayleigh台阶结构腔体内流动较平行圆盘间流动更加复杂,有涡胞结构存在;腔体内压强较高,具有更高的承载力;当200<Re<2 250时,流场中有1至4个不同数量的涡胞存在;随节流边厚度h(0.05～0.20 mm)和几何参数e(0.5～4.0)的增大,涡胞数量增多,尺寸增大,涡胞位置也发生变化;流体入口轴向速度对流场结构模拟结果有重要影响;同时,由于涡胞结构的影响,腔体壁面压强及近壁面速度分布是不均匀的.

In order to reveal the effect of flow characteristics on the load capacity of oil cavity,the flow of round Rayleigh step cavity in hydrostatic lift was divided into three regions： the axisymmetric jet impinging flow,radial source flow and film flow.The computational fluid dynamics（CFD） method was used to build a calculation model and the influences of geometry（e,h） parameters and the Reynolds number on the vortices were simulated.The results show that there are complex vortices in the flow field of the round Rayleigh step cavity,of which the pressure is higher than parallel disks flow.The number of vortices is different from 1 to 4 with the Reynolds number of 200Re2 250.The number and size of vortices are increased,and location is changed with the increasing of h（0.05-0.20 mm） and e（0.5-4.0）.The inlet velocity significantly affects the vortices structure and the distributions of wall pressure and velocity are uneven.