Thermohydrodynamic Lubrication Research Articles

The Contribution of Fluid Film Inertia to the Thermohydrodynamic Lubrication of Sector-Pad Thrust Bearings

This paper is concerned with the load carrying capacity of thermohydrodynamic lubricating films in sector pad thrust bearings; it combines the effects of the thermal wedge and fluid film inertia in one analysis. Particular emphasis is placed on fluid film inertia in a rotational fluid film analysis. The nonlinear partial differential equations are transformed into finite difference equations and a successive over-relaxation method is used to obtain numerical solutions to the equations using a digital computer. The convergence of iterations is accelerated by introducing a relaxation factor. The analysis shows that fluid film inertia significantly affects the loading capacity (or pressure distribution), and velocity profiles. Temperature variance caused by fluid film inertia is insignificant.

Thermohydrodynamic Lubrication in Laminar and Turbulent Regimes

The distribution of “effective viscosity”—assumed dependent on local shear and temperature—is obtained via iteration between the “long bearing” momentum and energy equations. In this treatment the shaft is isothermal and the bearing conducts heat only in the radial direction. This last assumption leads to essential simplifications: the bearing is replaced by an equivalent homogeneous boundary condition of the energy equation, which thus becomes amenable to solution by the Galerkin-Kantorovich method. The resulting effective viscosity is used to calculate the performance of finite journal bearings.

Application of finite element methods to thermohydrodynamic lubrication

AbstractA finite element formulation is presented for the equations governing the steady thermohydrodynamic behaviour of liquid lubricated bearings. This formulation permits application of the iterative solution scheme to bearings of arbitrary geometry.A generalized Reynolds equation resulting from the combination of the mass and momentum conservation equations is cast into variational form and used to derive general finite element equations. The method of weighted residuals with Galerkin's criterion is used to generate finite element matrix equations for the thermal energy equation. In addition to the finite element formulation, a discussion of appropriate finite difference techniques is also given for problems without complex geometry.As an example, the formulations are applied to obtain numerical solutions for a three‐dimensional sector thrust bearing operating in the thermohydrodynamic regime. Pressure, velocity and temperature distributions are give, and the thermohydrodynamic solutions are compared with the results of classical isothermal theory.