Computational fluid dynamics performance prediction for the hydrodynamic bearings of the VentrAssist rotary blood pump

Finite-volume computations are described for laminar flow in the hydrodynam ic bearings supporting 2 different versions of the impeller of the VentrAss ist rotary pump. Pressure boundary conditions are taken from prior computat ions of turbulent flow in the whole pump with frictionless sliding of the i mpeller on the inside of the pump body. By investigating various impeller p ositions, the true ride height is determined. Net lift and combined drag fr om all 8 bearings of the 4-bladed impeller are compared with predictions ba sed on 2-D theory. The computations also reveal the extent of net force and moment acting to move the impeller away from its nominal axis of rotation.