Department of Biomedical Engineering, Bahcesehir University, Istanbul, Turkey.
ASAIO J. 2013 May-Jun;59(3):230-9. doi: 10.1097/MAT.0b013e31828a6bc1.
Virtual design characteristics and performance of the first Turkish axial-flow left ventricular assist device (LVAD) are presented, with emphasis on rotor geometry. The patented rotor design includes a central flow channel carved inside the main block, which carries permanent magnets. A concentric rotor-stator gap minimizes the distance between respective magnets, improving electromagnetic efficiency and creating a second blood pathway. Dual sets of three helical blades, placed on the shaft and external surface of the rotor block, ensure unidirectionality. Hemodynamic performance was tested with computational fluid dynamics (CFD); and rotor-blade geometry was optimized, to maximize overall efficiency d and minimize backflow and wall shear stresses. For a shaft radius of 4.5 mm, rotor blade height of 2.5 mm, and blade inlet and exit metal angles of 67° and 32°, pump operation at the nominal head-flow combination (5 L/min and 100.4 mm Hg) was achieved at a rotor speed of 10,313 rpm. At the nominal point, backflow as percent of total flow was 7.29 and 29.87% at rotor inlet and exit, respectively; overall hydraulic efficiency reached 21.59%; and maximum area-averaged shroud shear was 520 Pa. Overall efficiency peaked at 24.07% for a pump flow of 6.90 L/min, and averaged at 22.57% within the flow range of 4-8 L/min. We concluded that the design satisfies initial rotor design criteria, and that continued studies with diffuser optimization and transient flow analysis are warranted.
介绍了第一台土耳其轴向血流左心室辅助装置（LVAD）的虚拟设计特点和性能，重点介绍了转子几何形状。专利转子设计包括在主块内部雕刻的中央流道，该流道承载永磁体。同心的转子-定子间隙使各个磁铁之间的距离最小化，提高了电磁效率并形成了第二条血液通路。两组共三个螺旋桨叶片，放置在轴和转子块的外表面上，确保了单向性。使用计算流体动力学（CFD）测试了血液动力学性能；并优化了转子叶片几何形状，以最大程度地提高整体效率 d，并最小化回流和壁面剪切应力。对于轴半径为 4.5 毫米、转子叶片高度为 2.5 毫米以及叶片进出口金属角为 67°和 32°的情况，在转子速度为 10313rpm 时，可在名义头流量组合（5L/min 和 100.4mmHg）下实现泵的运行。在标称点处，回流占总流量的百分比分别为转子进口处的 7.29%和出口处的 29.87%；整体水力效率达到 21.59%；最大平均遮罩剪切力为 520Pa。当泵流量为 6.90L/min 时，整体效率达到峰值 24.07%，在 4-8L/min 的流量范围内平均为 22.57%。我们得出的结论是，该设计满足初始转子设计标准，并且有必要进行扩散器优化和瞬态流分析的进一步研究。
