Blood flow analysis for the secondary impeller of an IVAS heart pump.

The rotodynamic heart pump (IVAS), designed by the Cleveland Clinic Foundation, includes a secondary flow path along the journal bearing, through a secondary impeller, and over the rotor outer surface. The flow behaviors of the blood through the journal bearing and the secondary impeller 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 patterns within the journal bearing, 2) the effect of the non-uniform bearing clearance on the flow patterns of the impeller cavity, 3) the flow patterns around a secondary impeller blade that include effects of tip clearance and the gap between the blade and the inner or outer side wall, 4) effects of the blade angles on the secondary impeller performance, and 5) the shear stress distribution.