BLOOD-FLOW ANALYSIS FOR THE SECONDARY IMPELLER OF AN IVAS HEART PUMP

The rotodynamic heart pump (IVAS), designed by the Cleveland Clinic Fo undation, includes a secondary now path along the journal bearing, thr ough a secondary impeller, and over the rotor outer surface. The flow behaviors of the blood through the journal bearing and the secondary i mpeller are investigated by a computational fluid dynamics method that solves the 3-dimensional Navier-Stokes equations using a new solution algorithm. Results of the analyses include: 1) the blood flow pattern s within the journal bearing, 2) the effect of the non-uniform bearing clearance on the flow patterns of the impeller cavity, 3) the flow pa tterns around a secondary impeller blade that include effects of tip c learance and the gap between the blade and the inner or outer side wal l, 4) effects of the blade angles on the secondary impeller performanc e, and 5) the shear stress distribution.