INERTIA EFFECTS IN A HYBRID BEARING WITH A 45-DEGREE ENTRANCE REGION

An investigation is presented that illustrates the effects of inertia on the flow and pressure field throughout a hybrid bearing with a 45 d egree entrance region. This type of bearing has been previously shown to offer better performance over the hybrid bearing with a normal entr y region. A two-dimensional planar approach is adopted and the resulti ng flow governing equations are solved using the Galerkin Weighted Res idual finite element method. This algorithm incorporates advanced stre amline upwinding method to evaluate the nonlinear effects of the conve ction terms. The results demonstrate the complex nature of the velocit y field and its subsequent impact on the pressure field. This comprehe nsive parametric study also shows why traditional lubrication approach es that typically exclude convection effects will become unreliable at high operating speeds of turbomachinery. A set of loss coefficients m odeling the pressure 'ram' effects are provided to illustrate the iner tia effects in the entrance region of the film lands. In a hybrid bear ing these effects have to be characterized according to the operating parameters of the bearing and the journal direction of rotation.