| Summary: | 碩士 === 國立中正大學 === 機械系 === 90 === Accurate calculation of bearing load capacity is an important task in the design or analysis of bearing systems. From the literature, it was found that the parametric studies of bearings have been made in laminar isothermal, laminar thermal, and turbulent isothermal regimes. Formulations, tables, or charts of bearing performance parameters in those regimes can be found in the literature. However, a complete parametric study for turbulent thermohydrodynamic bearings was not found in the literature.
The objectives of this study are to perform a complete parametric study for slider bearings and to establish the formulations of load capacity. Both infinitely-wide and finite width slider bearings were considered. The regimes investigated include isothermal and thermohydrodynamic. In all the cases, inertial effects were included. From the geometry, thermal boundary condition, and governing equations, the dimensionless parameters were obtained including the convergence ratio ( h* ), slenderness ratio ( B* ), dimensionless temperature-viscosity parameter ( Ecμ ), mean Reynolds number ( Rem ), Peclet number ( Pe ), ratio of mean film thickness to bearing length ( hm/L ), and thermal boundary condition parameter ( γ* ). Among these parameters, the effects of h*, B*, Ecμ and Rem are of the primary consideration. Models used in this study include inertial, thermal, and turbulent models. For infinitely-wide bearings, a collocation method was used, and for finite-width bearings, an efficient and general fluid film lubrication model (EGFLUM) was used.
From the results, it was found that pressure increases with the increase of convergence ratio or slenderness ratio. When mean Reynolds number increases, the pressure will increase as the turbulent intensity become greater. As Ecμ increases, the viscosity will decrease which yield a smaller pressure distribution. Current study used least square method to find out the formulations for the determination of bearing load capacity. With the equations provided, engineers and designers can quickly calculate load capacity using a calculator.
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