Theoretical and experimental studies on the effect of spiral groove–orifice restrictor position coupling on the performance of hybrid aerostatic–aerodynamic thrust bearing

To meet the requirements of high-speed and high-power rotational equipment for gas thrust bearings with large load bearing capacity and high stiffness, this study takes the spiral groove–orifice restrictor coupled hybrid aerostatic–aerodynamic thrust bearing (HATB) as the research object. Using computational fluid dynamics numerical simulation and performance experiments, this study investigates the influence of the relative position between the spiral groove and the orifice restrictor on gas flow characteristics, load bearing capacity, and stiffness of the HATB. Furthermore, the effects of gas supply pressure and rotational speed on the coupling interaction between the spiral groove and the orifice restrictor are analyzed. The results reveal that the orifice restrictor dominates the gas pressure distribution within the gas film of the bearing, while the spiral groove alters the gas pressure distribution at its location and adjusts the gas pressure distribution in adjacent regions. The coupling interaction between the spiral groove and the orifice restrictor exhibits significant dependence on the rotational speed of the thrust surface. Under stationary conditions or low rotational speeds, close proximity between the spiral groove and the orifice restrictor results in synergistic static performance enhancement. As the spacing increases, the coupling effect between the spiral groove and the orifice restrictor shifts from synergistically enhancing bearing performance to synergistically suppressing it. When the rotational speed exceeds a certain critical value, spiral groove and orifice restrictor could synergistically enhance the load bearing capacity and stiffness of gas bearing. Experimental findings demonstrate that under stationary conditions and large gas film thickness, the experiment load bearing capacity and experiment stiffness of HATB A1, HATB A2, and HATB A3 surpass those of orifice-throttled aerostatic thrust bearing. This study highlights that an optimized design of the relative position between the spiral groove and the orifice restrictor can improve both the load bearing capacity and stiffness of the HATB, offering valuable insight for the design of high-performance gas thrust bearings in precision applications.