Prediction of hemolysis tendency by shear stress in a pipe orifice blood flow

This paper describes a method of predicting hemolysis induced by turbulent shear stress (Reynolds stress) in simplified orifice pipe flow. In a centrifugal blood pump, serious hemolysis occurs at the impeller or the casing edge. The turbulent shear stress computed using a low-Reynolds number k-Ε model near the edge proves to be several hundred times the laminar shear stress (molecular shear stress). The peak turbulent shear stress is about 2 500 Pa, which is much larger than that obtained from a conventional hemolysis test using viscometer. Then the threshold of turbulent shear stress for hemolysis is determined by comparing with that obtained in hemolysis experiments of pipe-orifice blood flow.