Assessment of Hemolysis in a Ventricular Assist Axial Flow Blood Pump

Abstract

This article reviews the criteria for assessment of hemolysis used in simulating the flow through a ventricular assist axial flow blood pump. The object of study is a model of the flow path of an axial pump consisting of a flow straightener, impeller, and diffuser. In this study, blood is considered as an incompressible Newtonian fluid with constant viscosity and density. Its flow is considered as unsteady. In the process of simulation, non-interacting control particles are introduced into the computational domain. The trajectories of the particles represent the trajectories of red blood cell movement in blood. To calculate the equivalent shear stress applied to a particle in the stream, the stress tensor is calculated at each point of the trajectory. This paper presents an equation for conversion of the stress tensor components into the equivalent shear stress. The results of the conversion are used to construct experimental hemolysis curves. Based on the obtained data, the rate of hemolysis in the flow path is compared to that in other ventricular assist devices.