Flow Modelling in the Pneumatic Ventricular Assist Device with Mesh Deformation and Immersed Body Techniques - Investigation of Stagnation Zones

摘要

A Ventricular Assist Device (VAD) has to be modified to omit risks resulting from the geometry and flow structures. Engineers all around the world use innovations in design to make the VAD shape optimal. A method of simulating the blood flow through the artificial heart under transient conditions is presented. Changes in the VAD volume are obtained by mesh deformation and mechanical valve disc motion as immersed bodies are used to examine the flow pattern inside the chamber, especially stagnation regions. The results of simulation and analysis for the period corresponding to four cycles of the VAD are shown. The boundary conditions in this study are based on the investigations conducted previously within the Polish Artificial Heart Project and on the existing literature data.The fluid was defined as non-Newtonian, based on the Power Law model. The CFD ANSYS CFX v.12.1 code was used in the analysis. The geometrical model used in this work, referred to as POLVAD EXT, was designed and made at the Foundation of Cardiac Surgery Development, Zabrze. To control the flow through the VAD, single disc mechanical heart valves were used. The mechanical valves were designed at the Institute of Turbomachinery, Technical University of Lodz.