Lim W L, Chew Y T, Chew T C, Low H T
Department of Mechanical and Production Engineering, National University of Singapore, Singapore.
J Biomech. 1998 May;31(5):411-21. doi: 10.1016/s0021-9290(98)00026-8.
Particle Image Velocimetry (PIV), capable of providing full-field measurement of velocities and flow stresses, has become an invaluable tool in studying flow behaviour in prosthetic heart valves. This method was used to evaluate the performances of four prosthetic heart valves; a porcine bioprostheses, a caged ball valve, and two single leaflet tilting disc valves with different opening angles. Flow visualization techniques, combined with velocity vector fields and Reynolds stresses mappings in the aortic root obtained from PIV, and pressure measurements were used to give an overall picture of the flow field of the prosthetic heart valves under steady flow conditions. The porcine bioprostheses exhibited the highest pressure loss and Reynolds stresses of all the valves tested. This was mainly due to the reduction in orifice area caused by the valve mounting ring and the valve stents. For the tilting disc valves, a larger opening angle resulted in a smoother flow profile, and thus lower Reynolds stresses and pressure drops. The St. Vincent valve exhibited the lowest pressure drop and Reynolds stresses.
粒子图像测速技术（PIV）能够提供速度和流动应力的全场测量，已成为研究人工心脏瓣膜内流动行为的重要工具。该方法用于评估四种人工心脏瓣膜的性能；一个猪生物瓣膜、一个笼球瓣和两个具有不同开口角度的单叶倾斜盘瓣。流动可视化技术，结合从PIV获得的主动脉根部的速度矢量场和雷诺应力映射，以及压力测量，用于全面描绘稳定流动条件下人工心脏瓣膜的流场。在所测试的所有瓣膜中，猪生物瓣膜表现出最高的压力损失和雷诺应力。这主要是由于瓣膜安装环和瓣膜支架导致的孔口面积减小。对于倾斜盘瓣，较大的开口角度导致更平滑的流动剖面，从而降低雷诺应力和压降。圣文森特瓣表现出最低的压降和雷诺应力。
