EVALUATION OF BLOOD COMPATIBILITY OF A CENTRIFUGAL BLOOD PUMP BASED ON THE TRANSIENT FLOW VELOCITY MEASUREMENT FROM THE ROTATING FRAME.

发展了一种流动可视化方法，可以直接观察和测量心脏辅助离心泵叶轮内的相对速度分布。将含有分束器和直角棱镜的像旋转器应用于离心泵的双比例模型。用粒子图像测速仪(PIV)测量了叶轮的瞬时速度分布，结果还表明，叶轮的通道内充满了不同尺度的涡流，这似乎有助于防止叶轮与血液接触表面形成血栓。叶轮向出口的排放仅限于流道与出口重叠的时间段。这种不稳定被发现在泵的流体动力效率和径向推力方面是不利的。它是通过使用蜗壳来缓和的。然而，值得注意的是，流场的轴向变化被放大了。

Flow visualization method has been developed which enables the direct observation and measurement of the relative velocity distribution in the impeller of a centrifugal pump used for cardiac assist. The image rotator containing a beam splitter and a right-angle prism was applied to the double-scale model of a centrifugal pump. The transient flow velocity distribution was measured by the particle image velocimetry (PIV) technique.The results also demonstrated that the passages of the impeller were filled with vortices of various scales, which seemed to contribute to prevention of thrombus formation on the blood-contacting surface of the impeller. The emission from the impeller toward the outlet port was limited to the period when the passage overlapped the area of the outlet port. This unsteadiness was found to be adverse in terms of the pump's hydrodynamic efficiency and the radial thrust. It was moderated by the use of the volute casing. It should be noted, however, that the axial variation of the flow field was enlarged.