Computational hemodynamics of blood immersed devices

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Work on the heart pump led us to the problem of modelling hemolysis, the process by which red blood cells are destroyed. We have developed and published the first hemolysis model taking the form of a partial differential equation. Since blood immersed devices are often subjected to time-dependent flow conditions under turbulent and non Newtonian law of deformation we wish to extend and improve the capability of our hemolysis models to such extreme conditions. The study of blood flow through cardiac valves represents a considerable challenge. The transitory nature of the flow must be measured, or accurately simulated, as well as the strength of the forces induced by the movement of the blood. Specifically, the flow regime, with its low Reynolds number, must be characterized in order to validate the numerical prediction models of the flow on the one hand, and, on the other, to validate and develop models for hemolysis prediction. In design terms, the goal will be to minimize the hemolysis generated by the interaction between the surfaces of these devices and the blood flow. Up to now, in the absence of proven numerical methods, designers have had to rely on numerous and costly laboratory tests to predict hemolysis. The aim of our research is to develop mathematical models of hemolysis suited to the analysis and design optimisation of medical devices which are subject to unsteady flow phenomena. To achieve this, we have identified four objectives: 1.To pursue the development of advanced models of hemolysis; 2.To extend the hemolysis model to unsteady periodic and non-periodic flow; 3.To develop an adaptive methodology for finite element solution of hemolysis; 4.To assess the physical realism of hemolysis model for unsteady flow in cardiac valves.