Wernicke J T, Meier D, Mizuguchi K, Damm G, Aber G, Benkowski R, Nosé Y, Noon G P, DeBakey M E
Institute for Biomedical Engineering and Medical Information, University of Rostock, Germany.
Artif Organs. 1995 Feb;19(2):161-77. doi: 10.1111/j.1525-1594.1995.tb02306.x.
The Baylor/NASA Axial Blood Flow Pump has been developed for use as an implantable left ventricular assist device (LVAD). The pump is intended as an assist device for either pulmonary or systemic circulatory support for more than 3-months' duration. To date the pump provides acceptable results in terms of thrombus formation and hemolysis (IH of 0.018 g/100 L). A fluid dynamics analysis using flow visualization was performed to investigate the flow fields and to determine areas within the pump that could be improved. These studies focused upon the inflow area in front of the pump. A prototype axial flow pump assembly was constructed to facilitate the flow visualization studies. Particle image tracking velocimetry techniques were used to measure Amberlite particles suspended in a blood analog fluid composed of 63% water and 37% glycerin. This method used a pulsed (612 Hz) laser light to determine flow velocity profiles, shear stress, Reynolds numbers, and stagnant areas within the axial pump. These studies showed that the flow straightener (a vaned assembly in the pump inflow) reduced Reynolds numbers from 4,640 to 2,540 (at 8.5 L/min) and that the flow straightener exacerbates a discontinuity found between it and the impeller. Within the inflow area, a maximum of 80 N/m2 shear stress was measured, which is well below published blood damage thresholds. Design variations were investigated resulting in a smoother flow transition between flow straightener and impeller. These variations must be investigated further to establish a correlation with hemolysis and thrombus formation.
贝勒大学/美国国家航空航天局轴流血泵已被开发用作植入式左心室辅助装置（LVAD）。该泵旨在作为一种辅助装置，用于肺循环或体循环支持，持续时间超过3个月。迄今为止，该泵在血栓形成和溶血方面（溶血指数为0.018 g/100 L）提供了可接受的结果。进行了使用流动可视化的流体动力学分析，以研究流场并确定泵内可改进的区域。这些研究集中在泵前方的流入区域。构建了一个原型轴流泵组件，以促进流动可视化研究。粒子图像跟踪测速技术用于测量悬浮在由63%水和37%甘油组成的血液模拟流体中的Amberlite颗粒。该方法使用脉冲（612 Hz）激光来确定轴流泵内的流速分布、剪切应力、雷诺数和停滞区域。这些研究表明，整流器（泵流入处的带叶片组件）将雷诺数从4640降低到2540（在8.5 L/min时），并且整流器加剧了其与叶轮之间的不连续性。在流入区域内，测得的最大剪切应力为80 N/m2，远低于已公布的血液损伤阈值。研究了设计变化，以实现整流器和叶轮之间更平滑的流动过渡。这些变化必须进一步研究，以建立与溶血和血栓形成的相关性。
