Abstract
Flow visualization was conducted to clarify the low flow conditions or the leakage flow conditions to prevent thrombus formation in MERA centrifugal pump for extracorporeal circulation. A 3x similarity model was used to analyze precise flow in the impeller-casing gap using a high-speed video camera (Phantom) and a particle tracking velocimetry (4-frame PTV). The laser light sheet (4W) illuminated the 20%-position plane from the inner top plane of the casing, where the maximum velocity was expected in the gap. The pump conditions were selected to keep the ratio of rotational speed and flow rate. Obtained normal velocities to the integral path were integrated to obtain the leakage flow rate. The obtained leakage flow rate in the upper gap was almost 20-30% of the outflow rate for all 5 conditions. Future visualization would clarify whether the leakage flow is constant or not if the rotational speed, namely the pump pressure, is constant.
