CFD-Based Investigation on Effects of Orifice Length–Diameter Ratio for the Design of Hydrostatic Thrust Bearings

Abstract

Orifice-restricted hydrostatic thrust bearings are broadly employed in ultra-precision machine tools, aerospace industries, and so forth. The orifice length–diameter ratio (OLDR) is one of the significant geometrical parameters of the orifice-restricted hydrostatic thrust bearing, which directly affects the performance of the bearing. To accurately guide the design of the hydrostatic thrust bearing, the effect of the OLDR on the performance of the hydrostatic thrust bearing needs to be thoroughly and scientifically investigated, especially for ultra-precision machine tools. In this paper, the influences of various OLDRs are comprehensively studied using the computational fluid dynamics (CFD) approach on the pressure pattern, velocity, turbulent intensity, and vortices, as well as the load capacity, stiffness, volume flow rate, and orifice flow resistance of the hydrostatic thrust bearing under identical operating conditions. The obtained results show that there are differences in performance behaviors of the hydrostatic thrust bearing caused by different OLDRs. Some new findings are obtained, particularly in the second-order small vortices which appear in the annular recesses with all OLDRs except that of 2, and the flow resistance does not always increase with increasing OLDRs. Finally, the proposed CFD approach is experimentally validated.

Influence of magnetorheological lubricant behavior on the performance of annular recessed orifice compensated non-textured/textured thrust pad bearing

“…where for an orifice restrictor, C s2 is the dimensionless design parameter of the restrictor. The restrictor design parameter ( C s2 ) is a function of various parameters such as discharge coefficient (ψ d ), supply pressure ( p s ), orifice diameter (d), reference fluid film thickness (h r ), and lubricant properties (μ, ρ) as shown in the following relation 7,44 :…”

“…The restrictor design parameter false( C ¯ s 2 false) is a function of various parameters such as discharge coefficient false( ψ d false), supply pressure false( p s false), orifice diameter false( d false), reference fluid film thickness false( h r false), and lubricant properties 0.25em false( μ , ρ false) as shown in the following relation 7,44 :…”

“…Orifice restrictors are the most widely used compensating devices for hydrostatic bearings because of their small size and ease of manufacturing. [5][6][7][8] Chen et al 9 examined the effect of compensating devices on the stability of hybrid bearings. They reported a better stability for the bearing compensated with an orifice restrictor in comparison to the capillary compensated bearing.…”

Design of a Hydrostatic Spindle and Its Simulation Analysis with the Application to a High Precision Internal Grinding Machine

“…To compare with no pocketed, spherical shape and rectangular shape, they found the pressure distribution and LCC increase respectively [20]. Gao et al focused on the influence of orifice chamber types of ultra-high-speed air spindles [21,22]. The flow characteristics are determined by such bearing parameters as the fluid film thickness, supply pressure and geometrical parameters of the restrictor [23,24].…”

Structure design and performance analysis of aerostatic thrust bearing with compound restrictors

“…Zheng et al [18] experimentally verified that aerostatic thrust bearing compensated by a restrictor with multi-orifice series has higher maximal stiffness compared to the bearing with traditional orifice type restrictor. Gao et al [19] investigated the effects of orifice length-diameter ratio on the performance of aerostatic thrust bearing by using CFD. Kodnyanko et al [20] improved the dynamic performance of active aerostatic bearing by using elastic orifices.…”