Static Performance Analysis of Integral Top Foil Gas Dynamic Thrust Bearings
The integral top foil gas dynamic pressure thrust bearing has the advantages of simple manufacturing process and high load capacity,which consists of several bearing sectors with independent bump foil,but has a complete annular top foil sheet.In order to investigate the working mechanism and static performance of this new bearing,the corresponding static performance analysis model was proposed and the cyclic boundary coupling condition was used to set the pressure at the inlet and outlet of the gas stream to be equal.The effects of the speed,minimum film thickness and wedge height on the static performance of the integral top foil thrust bearing were analyzed through numerical simulations,and the analysis re-sults were compared with those of the separated top foil bearing under the same operating conditions.The results show that the top foil sheet of the integral top foil bearing will change from wedge-step to wedge-land geometry under load,and the trailing edge of the single tile sector will be bent upward due to deformation to produce a secondary wedging effect,thus forming two air film pressure peaks.And the integral top foil bearing also has a larger bearing area than the separated type bearing,so its load capacity will be higher.Due to the negative pressure zone at the top foil step,the optimal wedge height interval of the inegral top foil is delayed compared with the separated top foil,and a higher load capacity and a smaller fric-tion torque can be achieved when the wedge height is around 50 μm.When the minimum film thickness is increased,both the load capacity and the frictional torque are reduced.
integral top foilgas foil thrust bearingsecond wedging effectstatic performancesolid-fluid coupling
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