空气静压轴承流场对微振动的影响机制

Influence Mechanism of Flow Field on Micro-Vibration of Aerostatic Bearing

为讨论空气静压轴承微振动的影响因素,针对轴承间隙的流场特性进行仿真分析,探讨流场雷诺数与微振动的关系。首先在不同的供气压下,针对轴承间隙进行跨音速流动分析,研究流场结构;其次,分析雷诺数对于漩涡流所致激励力的影响,并进一步采用流固耦合方法,讨论雷诺数对于微振动的影响;最后,建立近似模型讨论气腔容积、小孔孔径、气膜厚对流场最大雷诺数的影响,即研究轴承参数对漩涡激励大小的影响。结果表明:流场最大雷诺数可用以表征漩涡流所致扰动激励的强弱,但微振动还取决于气膜-被支承件系统的动力学性能;在气腔容积较小时,漩涡激励作用更弱,意味着轴承运转的稳定性更好。相关流动机制分析可为以削弱微振动为目的的轴承设计提供参考。

In order to investigate the influence factor of the aerostatic bearing micro-vibration,the numerical simulation was conducted for the aerostatic bearing clearance flow field,and the relationship between the Reynolds number and the micro-vibration was discussed.Firstly,the transonic flow field structure of the aerostatic bearing clearance was studied under several sets of air supply pressure.Then the influence of Reynolds number on the vortex flow-induced excitation was discussed,and the structure-fluid coupling method was further used to investigate the influence of Reynolds number on the micro-vibration.Finally,the approximate model was established to study the influences of the air pocket volume,orifice diameter,and air film thickness on the maximum Reynolds number in the flow field,i.e.the influence of bearing parameters on vortex flow-induced excitation.The results indicate that the maximum Reynolds number of the flow field can be used to represent the strength of the vortex-induced excitation.However,the micro-vibration also depends on the dynamic performances of the air film-floating facility system.With smaller air pocket volume,the vortex excitation is weakened,and it means that the stability of the aerostatic bearing is improved.The flow mechanism analysis can provide a reference for the aerostatic bearing design to reduce the micro-vibration.