Computational hemodynamics of blood immersed devices

对心脏泵的研究使我们遇到了模拟溶血的问题，溶血是红细胞被破坏的过程。我们已经开发并发表了第一个溶血模型采取的形式偏微分方程。由于血液浸没器械通常在湍流和非牛顿变形定律下经受时间相关的流动条件，因此我们希望将我们的溶血模型扩展并提高其在此类极端条件下的能力。通过心脏瓣膜的血流的研究代表了相当大的挑战。必须测量或准确模拟流动的瞬时性质，以及由血液运动引起的力的强度。具体而言，必须表征具有低雷诺数的流态，以便一方面验证流的数值预测模型，另一方面验证和开发溶血预测模型。在设计方面，目标是尽量减少这些器械表面与血流之间相互作用产生的溶血。到目前为止，在没有经过验证的数值方法的情况下，设计人员不得不依靠大量昂贵的实验室测试来预测溶血。我们研究的目的是开发适用于分析和设计优化的医疗器械，这是不稳定的流动现象的溶血的数学模型。为了实现这一目标，我们确定了四个目标：1.追求先进的溶血模型的发展; 2.将溶血模型扩展到非定常周期性和非周期性流动; 3.开发一种自适应的溶血有限元解的方法; 4.评估心脏瓣膜非定常流动的溶血模型的物理真实性。

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.