Prediction of Hemolysis Tendency by Shear Stress in a Pipe Orifice Blood Flow

Abstract

This paper discribes 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 numberκ-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 2500Pa, which is much larger than that obtained from a conventional hemolysis test using viscometer. Then the threshould of turbulent shear stress for hemolysis is determined by comparing with that obtained in hemolysis experiments of pipe-orifice blood flow.