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

本文提出了一种直接观察和测量心脏辅助离心泵叶轮内相对速度分布的流动显示方法。将由分束镜和直角棱镜组成的像旋转器应用于离心泵的双尺度模型。利用粒子图像测速技术（PIV）测量了叶轮内的瞬时流速分布，结果表明叶轮内的通道内充满了不同尺度的旋涡，这些旋涡有助于防止叶轮与血液接触表面的血栓形成。从叶轮向出口的排放被限制在通道与出口区域重叠的时期。这种不稳定性被认为是不利的泵的流体动力效率和径向推力。这是缓和的使用蜗壳。然而，应该注意的是，流场的轴向变化被放大。

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.