Development of the Multistage Centrifugal Blood Pump for the Extended Use of Rotary Blood Pumps

本文介绍了一种新型多级叶轮离心泵的研制。多级叶轮的使用导致产生高压而不增加马达的旋转速度。这种结构的直接优点将是减少装置中的血细胞破坏（血液创伤）的量。第一台样机是针对流量为3. 0 L/min、压差为500 mmHg的虚拟工况设计的。原型采用以下设计特征，以确保产生高压。1.吸入蜗壳在进口管2中。高压叶轮轮廓3.双蜗壳，以尽量减少对叶轮的径向推力第一个原型证明了足够的泵的性能。对装置内部流场的CFD分析表明，需要在装置中的血细胞破坏和血栓形成方面进行设计改进。1在叶轮上添加前护罩2在双蜗壳的舌部中使用更宽的间隙3使用带护罩的回流叶片具有上述改进的第二个原型由于增加了流量，因此水力性能稍低。与设计变更相关的内部泄漏流，以增强器械的冲洗条件。然而，我们成功地将最大剪切应力降低到超过血细胞破坏的致死值，并消除了可能导致血栓形成的停滞区域。

The present study deals with the development of a novel centrifugal pump which consists of the multistage impeller. The use of a multistage impeller leads to generation of high pressure without increasing the rotational speed of the motor. The direct advantage of this structure will be the decreased amount of the blood cell destruction(blood trauma) in the device.The first prototype was designed for the virtual working condition of the flow rate of 3.0 L/min and the pressure difference of 500 mmHg. The prototype employs the following design features to ensure generation of high pressure.1. the suction volute in the inlet passage2. the impeller profile for high pressure3. the double volute to minimize the radial thrust on the impellerThe first prototype demonstrated the sufficient pump performance. The CFD analysis of the internal flow field of the device has revealed the need for design improvement in terms of the blood cell destruction and thrombus formation in the device.1 addition of the front shroud to the impeller2 use of the wider gap in the tongue of the double volute casing3 use of the shrouded return vaneThe second prototype with the above improvements demonstrated a bit lower hydraulic performance due to the increase in the internal leakage flow associated with the design change to enhance the wash-out condition of the device. However, we succeeded in decreasing the maximum shear stress over the lethal value for blood cell destruction and in elimination of the stagnant area which possibly leads to the thrombus formation.