When the surface roughness is comparable to the surface separation in a hydrodynamic thrust bearing, the effect of the surface roughness should be considered. In the condition of low bearing clearances such as on the scales of 1 nm and 10 nm, normally not only the surface roughness but also the physically adsorbed layer on the bearing surface should be simultaneously considered in evaluating the bearing performance. The present paper presents the numerical calculation results of the surface roughness influences on the hydrodynamic pressure and carried load of the inclined fixed pad thrust bearing with low bearing clearances when the effect of the adsorbed layer is incorporated. It is shown that the influence of the surface roughness is strongly dependent on the adsorbed layer and it is significantly increased with the increase in the interaction strength between the fluid and the bearing surface when the bearing clearance is low. For a weak fluid-bearing surface interaction, the results are close to those obtained from the classical hydrodynamic theory indicating the increase in the hydrodynamic pressure and carried load of the bearing with the increase in the surface roughness, while for the medium or strong fluid-bearing surface interactions, this surface roughness effect is much stronger. The results reveal the new mechanism in the studied model of the bearing regarding the coupled effects of the surface roughness and the physically adsorbed layer on the bearing surface.

当表面粗糙度与流体动力推力轴承中的表面分离相当时，应考虑表面粗糙度的影响。在轴承游隙较小的情况下，如1 nm、10 nm级别，评价轴承性能时，通常不仅要考虑表面粗糙度，还要同时考虑轴承表面的物理吸附层。本文给出了考虑吸附层效应时表面粗糙度对小轴承游隙倾斜固定瓦推力轴承动水压力和承载载荷影响的数值计算结果。结果表明，表面粗糙度的影响很大程度上取决于吸附层，并且当轴承游隙较低时，随着流体与轴承表面之间相互作用强度的增加，表面粗糙度的影响显着增加。对于弱流体-轴承表面相互作用，结果与经典流体动力学理论获得的结果接近，表明轴承的流体动压力和承载载荷随着表面粗糙度的增加而增加，而对于中或强流体-轴承表面相互作用，这种表面粗糙度效应要强得多。结果揭示了轴承研究模型中关于表面粗糙度和轴承表面物理吸附层耦合效应的新机制。