微孔节流器静压气体止推轴承性能分析*

传统固有孔节流静压气体止推轴承研究的理论基础均建立在节流孔直径远大于气膜间隙的前提下,为了探究与气膜间隙同一数量级的微孔节流器静压气体止推轴承的静态性能,建立微孔节流静压气体止推轴承模型,通过CFD软件进行三维仿真,分析不同气膜间隙、孔径、供气压力对轴承静态特性的影响,并与环面节流器静压气体止推轴承进行对比。结果表明:无论是微孔节流器还是环面节流器,在节流孔出口处均有压降出现,但微孔节流器相对于环面节流器在节流孔出口边缘处速度和压力变化较为平缓;随着气膜间隙的增大轴承承载力减小,随着微孔节流器孔径减小轴承刚度增大,相同孔径下供气压力越大轴承承载力和刚度越大。

Performance Analysis of Microporous Throttling Aerostatic Thrust Bearing

The theoretical basis of traditional orifice type aerostatic thrust bearing is based on the premise that the orifice diameter is much larger than the gas film clearance.In order to explore the static performance of aerostatic thrust bearing with microporous restrictor of the same order of magnitude as the gas film clearance,the model of microporous restrictor aerostatic thrust bearing was established,and the three dimensional simulation was carried out by CFD software to study the influence of gas film clearance,aperture and gas supply pressure on the static characteristics of the bearing.The simulation results were compared with that of annular throttling hydrostatic gas thrust bearing.The results show that there is a pressure drop at the orifice outlet for both microporous and annular throttling.The velocity and pressure change of the microporous restrictor at the edge of the orifice outlet is more gently than that of the annular restrictor at the edge of the orifice outlet,and the bearing stiffness is improved.The bearing capacity of the bearing is decreased with the increase of gas film clearance,the bearing stiffness is increased with the decrease of the orifice diameter of the microporous restrictor.Under the same aperture,the larger the air supply pressure,the greater the bearing capacity and stiffness.