Knoch M, Reul H, Kröger R, Rau G
Helmholtz-Institute for Biomedical Engineering, Aachen University of Technology, Federal Republic of Germany.
J Biomech Eng. 1988 Nov;110(4):334-43. doi: 10.1115/1.3108450.
In a 3:1 scaled model of the human aorta models of the Omniscience, Björk-Shiley Convexo-Concave, Björk-Shiley Monostrut, Medtronic-Hall, Duromedics (Hemex) and the Saint Jude Medical heart valve prostheses are studied in steady flow representing the systolic peak flow phase. Detailed flow visualization experiments show flow separations at all inner ring surfaces as well as at most of the occluders. The resulting stagnation areas increase the risk of thrombus accumulation. Flow separations also stimulate vortex formation and turbulent mixing at the downstream jet boundaries and thus may intensify blood damage by turbulent shear stresses. The different influences of struts and occluder guides on the flow around the occluders are discussed. The effects of the individual valve components on the flow fields are analyzed and correlated with the resulting pressure losses.
在人体主动脉的3:1比例模型中，对Omniscience、Björk - Shiley凸凹型、Björk - Shiley单支柱型、Medtronic - Hall、Duromedics（Hemex）以及圣犹达医疗公司的心脏瓣膜假体模型进行了研究，这些研究处于代表收缩期峰值血流阶段的稳定流中。详细的流动可视化实验表明，在所有内环表面以及大多数封堵器处都存在流动分离现象。由此产生的停滞区域增加了血栓积聚的风险。流动分离还会在下游射流边界处刺激涡旋形成和湍流混合，因此可能会因湍流剪应力而加剧血液损伤。讨论了支柱和封堵器导向装置对封堵器周围流动的不同影响。分析了各个瓣膜组件对流场的影响，并将其与由此产生的压力损失相关联。
