Computational fluid dynamics analysis of hydrodynamic bearings of the VentrAssist rotary blood pump.

The computational fluid dynamics (CFD) package CFX-TASCflow was applied to simulate the flows through the blood pump hydrodynamic bearings. The three-dimensional flow patterns through the bearings were predicted and the hydraulic performance analyzed. The computations were carried out at 3 axial positions of the pump impeller. Net lift force away from the nearer part of the housing increased when the impeller moved closer to this part. Radial force and drag force were also found. Separated flows were observed at the leading and trailing edge of the bearing gap. To test the CFD package, a series of two-dimensional computations were also carried out for various bearing geometries. The results were compared with published experimental data.