圆形静压油腔流场特性的PIV实验与数值模拟研究

利用粒子图像测速技术(Particle Image Velocimetry, PIV)和计算流体动力学(CFD)方法,研究了高档数控机床液体静压支承系统中油腔内部的流场特性,包括入口雷诺数(Re)、油腔深度(H)和封油边间隙(h)对油腔内部流场的涡胞结构、壁面压强及剪应力分布等的影响。研究结果表明：实验结果与数值模拟结果相一致;油腔内部存在复杂的涡胞结构;随Re(70~1400)的增大,涡胞数量由1个增加为3个,涡胞尺寸和位置也不断变化;随着油腔深度H从6mm增大到18mm,涡胞尺寸逐渐增大,但涡胞数量减小;随封油边间隙h的增大,涡胞尺寸明显增大;相同条件下,增大入口雷诺数Re或减小封油边高度h都会增大承载面压强和剪应力。该结论为提高数控机床静压油腔的稳定性和承载力提供理论依据。

PIV MEASUREMENTS AND NUMERICAL SIMULATION FOR FLOW CHARACTERISTICS IN ROUND HYDROSTATIC OIL CAVITY

Using particle image velocimetry (PIV) experiments and CFD numerical simulation, the flow characteristics of the oil cavity in the hydrostatic support system of high-end CNC machine tools have been investigated. The influences of inlet Reynolds number (Re), oil cavity depth (H) and clearance height (h) on vortex structures, wall pressure and shear stress distribution in the oil cavity have been studied. The results show that the simulation results agree well with experimental results. There exist complex vortex structures in oil cavity. The vortices number varies from one to three and the vortices size and positions change as Re (70~1400) increases. The vortices size increases and vortices number decreases as H varies from 6mm to 18mm. As h increases, the vortices size increases obviously. The wall pressure and shear stress increase as Re increases and h decreases in the same conditions. The results provide a foundation for improving the stability and carrying capacity of hydrostatic oil cavity.