The time-dependent flow across a model of a mitral tilting disk valve and the left ventricle

摘要

Employing computational fluid dynamics methods (CFD) to simulate the flow field across mechanical heart valves (MHV) might result in improved designs. CFD simulations give a detailed description of the unsteady flow field and might be extensivelyused for optimization of the designs or for isolating factors (that in many cases cannot be isolated by experimental techniques). However, the numerical simulation of such flows is difficult, mainly because of the complex character of the flow and theenclosure. It is 3-D and unsteady, it involves complex moving geometry and the motion of the mitral valve is dictated by the interaction with the flow, to list a few of the complexities.The numerical simulation of the full problem is beyond the routine capabilities of existing computational resources. Therefore, simplified models are sought in an attempt to allow such computations to be utilized in the design cycle. In this context, thepresent work studies the importance of unsteady effects on the flow field across a mitral valve in its fully open phase in the cardiac cycle. Since in a significant part of the diastole, the mitral valve is fully open, we are interested whether asimulation of the flow for a fixed valve case (in the fully open position) can approximate accurately enough the real flow, including the moving valve.