Numerical simulation of fluid-structure interaction for tilting-disk mechanical heart valves
According to the United States Department of Health and Human Services, 27.1 million non-institutionalized adults were diagnosed with heart disease in 2010. The number of deaths associated with heart disease in 2009 was reported to be 599,413, claiming the lives of 195 out of every 100,000 people, which makes heart disease the number one killer in the U.S. Even though mechanical heart valves (MHVs) have proven to save lives in many of these cases, they are still not perfect, and complications arising from their design have reduced their application. To better understand the important factors and pursue remedies, numerous experimental investigations have been conducted; however, despite impressive improvements, small-scale studies suffer from lower levels of accuracy and sometimes are very costly to conduct. As in many other areas of research, numerical simulations can be helpful in reducing costs and supplementing such experimental work. The computational effort in this thesis focused on the numerical analysis of current tilting-disk MHVs. In this work, an implicit fluid-structure interaction (FSI) simulation of the Bjork-Shiley design was carried out using in-house codes implemented in the commercial code software FLUENT. In-house codes in the form of journal files, schemes, and user-defined functions (UDFs) were integrated to automate the inner iterations and enable communication between the fluid and the moving disk at the interfaces. Based on the investigation of the current simulations, a new design aiming at improving the hemodynamic performance is suggested. The hemodynamics of flow in current tilting-disk valves was compared with the suggested design, and it is concluded that the suggested design has a better hemodynamic performance in terms of shear stress values and residence times.
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Aerospace Engineering