遠心型血液ポンプ羽根車の軸支持部に作用するふれまわり流体力(流体工学,流体機械)  [in Japanese] The Rotordynamic Fluid Forces on a Shaft Support Part of Artificial Heart Pump Impeller in Whirling Motion(Fluids Engineering)  [in Japanese]

In centrifugal pumps for artificial hearts, a magnetic drive and lightly loaded journal bearing system are often used to avoid leakage and to minimize the damage on blood cells. In such system, the rigidity of the shaft support part is so small and the impeller usually rotates over the critical speed. For such cases, the rotordynamic fluid forces play an important role for the stability of operation. In the present study, the characteristics of the rotordynamic fluid forces on the shaft support part are examined. The destabilizing fluid force which encourages the whirling motion of the rotor occurs in the positive whirl speed region and the destabilizing region is decreased as the flow rate is increased. The destabilizing region is influenced by the pre-swirl at the inlet of the shaft part and the destabilizing region is increased in the positive whirl speed region as the pre-swirl is increased. The fluid forces with static eccentricity are also measured. Finally, the flow visualization around the rotor is carried out and a Taylor-vortex structure is observed.