Numerical Flow Simulation of Three-Dimensional Aero-Shaped Artificial Heart Valve

• Main Authors: Tsung-Chu Lee, 李琮祺
• Other Authors: Pong-Jeu Lu
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/43642554433759682826

碩士 === 國立成功大學 === 航空太空工程學系碩博士班 === 91 === A three-dimensional (3D) Aero-Shaped-Valve was designed by using the previously optimized two-dimensional (2D) ASV-1 configuration as the sectional shape. Computational Fluid Dynamics was employed to analyze this ASV aorta flow to see whether hemodynamic properties can be improved as concluded previously in the 2D optimization. The 3D ASV occluder is a low aspect-ratio configuration, which may generate leading-edge vortices that are not seen in the 2D ASV-1 flow. High-speed fluid particles were entrained into the low-speed separation zone, hence greatly energize the stagnant, recirculatory leeside flowfield of the occluder. This vortex-induced mixing effect is the main 3D mechanism that reduces the possibility of thrombus formation. In the present 3D study, the zero-moment rotation center was found to be located at the 0.325c position, which, in the main time, can reduce the total pressure loss as compared to that using the 2D optimized rotation center position. The trailing-edge of the 3D ASV occluder was modified using a rounded trailing-edge (Rt.e.=0.05c) to strengthen the structural integrity. It was found that this trailing-edge modification does not change the flow properties significantly. Comparing to the convectional plate-like occluder, the hemodynamic characteristics can be improved in terms of lower total pressure loss, smaller stagnation region, reduced turbulent Reynolds stresses and wall shear stress for the ASV occluder design. Occluder configuration is hence justified critical to the heart valve design and hemodynamics can be significantly improved as airfoil-like shapes are considered.