为了揭示气体静压轴承微振动的产生要素, 从微观流场角度出发通过计算流体动力学(CFD)对气膜流场进行三维数值大涡模拟(LES)与分析。首先, 设计不同单一变量从而相对气容不同的五组仿真实验组, 通过仿真研究内部气容对微观流场的影响。接着, 通过观察不同结构的仿真结果, 从各种参数中找出可能引发微振动的激励振源。最后, 采用不同压力的供气进行仿真说明内部压强对内部流场的影响。计算结果表明, 当相对气容约在1%时, 一定的内部气容就会明显导致气体静压轴承微振动; 均压腔附近的压力波动是诱发微振动的激励振源; 内部压强的高低则与振动幅度有着一定的联系。总之, 气体静压轴承的微振动与微观流场的变化有着直接的联系, 而流场转捩产生的涡旋是其主要原因。

To reveal the factors responsible for generation of the nano-vibration of aerostatic bearings, computational fluid dynamics and three-dimensional numerical large eddy simulations were employed herein for the analysis of the air film flow field from the perspective of the microscopic flow field. First, five simulated experimental groups were designed to investigate the effect of the internal gas volume on the microscopic flow field using different single variables and under different relative gas capacities. Subsequently, the simulation results of different structure parameters were analyzed, according to which the excitation sources that can result in generation of nano-vibrations were determined. Finally, the influence of internal pressure on the flow field was illustrated via the simulation of different supply pressures. A certain internal gas volume leads to the nano-vibration of aerostatic bearings when the relative gas capacity is approximately 1%. The pressure fluctuation near the equalizing cavity may be the excitation source responsible for inducing nano-vibration; the internal pressure also influences the amplitude of the vibration to a certain extent. In conclusion, the changes in the microscopic flow field directly in fluence nano-vibration, while the vortex generated uponflow field transition is the major factor causing it.