Flow Modelling in the Pneumatic Ventricular Assist Device with Mesh Deformation and Immersed Body Techniques - Investigations of Flow Pattern

摘要

A Ventricular Assist Device (VAD) is very often the only opportunity for a person suffering from serious heart defects to stay alive. VADs currently in use are subjected to constant modifications. Engineers all around the world use innovations in design to make the VAD optimal. Due to a very specific use of the VAD, engineering skills and intuition are not sufficient tools to design a VAD free of defects. 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. The results and their 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.