Basic Research on Seal-less Centrifugal Blood Pump

我们的目标是改进无密封离心式血泵(章动型和磁悬浮型)作为下一代人工心脏的性能。I.营养型：为了在较低的转速下获得更高的压力，我们用双作用的起伏圆盘取代了螺动叶轮。通过缩小盘片边缘与壳体之间的间隙，以及加宽隔膜侧的进气口，提高了泵的性能。II.磁悬浮式：(1)动物实验证明，该泵具有一年以上的使用寿命。(2)在没有流量计和压力传感器的情况下，可以根据测量的电机电流和电机转速来估算流量和压差。(3)利用激光位置传感器对旋转叶轮磁悬浮的稳定性进行了测量。这表明径向直叶片是最稳定的。计算流动分析：(1)采用低雷诺数湍流模型计算节流孔内湍流剪应力的分布，确定了溶血剪应力的阈值。(2)用带扩散速度的离散涡方法分析了章动圆柱的绕流问题。

We aim at improving the performance of seal-less centrifugal blood pumps (nutation on type and magnetic suspension type) as an artificial heart of next generation.I.Nutation Type : We replaced the nutating impeller by an undulating circular disc of double action in order to obtain the higher pressure at the lower rotational speed. The pump performance proved to be improved by narrowing the clearance between the edge of disc and the casing, and also by widening the inlet port of diaphragm side.II.Magnetic suspension Type : (1) Animal experiments verified that the present pump has endurance of more than one year. (2) Without flow meter and pressure transducers, the flow rate and pressure difference can be estimated from the measured motor current and the motor speed. (3) The stability of rotational impeller magnetically suspended was measured by Laser position sensers. This show that the radially straight vane is most stable. (4) By viewing from the same rotational coordinate as rotating impeller, the flow patterns in various kinds of impellers were revealed.III.Computational Flow Analysis : (1) Distribution of turbulent shear stress in the orifice were computed using the low Reynolds number turbulent model and then the threshold of shear stress for hemolysis were determined. (2) Flows around a nutating circular cylinder were analyzed by the discrete vortex method with diffusion velocit.