不同边界条件下液体静压油腔流场与承载稳定性数值研究

 液体静压支承系统因其承载性能好、摩擦阻力小、精度高、稳定性好的优点,逐渐成为现代高精度数控机床中的核心部件。研究不同情况下油腔承载稳定性对于提高机床加工精度具有重要意义。本文数值研究了不同边界条件以及不同转台转速下液体静压油腔内的流动状态和稳定性。选取圆形静压油腔为计算模型,转台转速范围为0-5m/s。研究结果表明：静态下,油膜厚度对油腔承载能力有很大影响,随着油膜厚度的增加,油腔压强降低,导致油腔承载能力降低;润滑油黏度增加,减弱了涡旋影响,增强了油腔稳定性;油腔深度和油腔入口半径增大,增大了涡旋影响,降低了油腔稳定性;转台的转动造成油腔中的压强分布不均,油腔压强沿转台运动的方向逐渐提高。提高转台转速,油腔内部流场中的涡旋位置和大小也会随之变化,入口附近的涡旋逐渐减弱并远离入口。涡旋的位置影响了油腔压强分布,贴于上壁面的涡旋导致上壁面压强上升,而远离上壁面的涡旋导致上壁面涡旋处的压强下降。

Numerical Simulation of Flow Field and Carrying Stability in Hydrostatic Oil Cavity Under Different Boundary Conditions

Due to its good carrying performance, low frictional resistance, high precision and stability, the hydrostatic support system becomes the core component in high-precision CNC machine tools. The study of the oil cavity's carrying stability is important in order to improve the precision of machine tools. In this paper, the flow and the bearing carrying capacity of the cycloidal hydrostatic oil cavity in a hydrostatic turntable system is numerically studied for rotating speed ranging from 0 to 5m/s of the turntable and under varied boundary conditions. The results show that the static bearing capacities of the oil cavity are reduced with the increase of oil film thickness. By increasing the lubricant viscosity, the effect of vortex will be weakened and the stability of the oil cavity will be enhanced. With the increase of the oil cavity's depth and the inlet radius, the vortex effect will be enhanced and the stability of the oil cavity reduced. The carrying capacity of the oil cavity diminishes with the increase of the oil film thickness. The oil cavity pressure due to the turntable's rotation is unevenly distributed and increases along the direction of the turntable's motion. With the increase of the turntable speed, the location and the size of the vortex vary in the oil cavity flow field and the strength of the vortex nearby the entrance is gradually weakened and the vortex goes away from the entry. The distribution of the pressure is determined by the location of the vortex. When the vortex is near the wall, the wall pressure will increase at that location. Otherwise, the wall pressure will decrease.