A FLOW VISUALIZATION STUDY OF THE NCVC CENTRIFUGAL BLOOD PUMP

A compact centrifugal pump, NCVC-1, has an open-type impeller with 6 c urved vanes, and it is characterized by no shaft and no seal. A tunnel is placed in the center of the impeller-rotor assembly to irrigate th e back space behind the rotor. To evaluate the flow, we performed 3 vi sualization methods: tracer, oil film, and injection streak line metho d. The flow, observed by the tracer method in NCVC-1, indicated little turbulence along vanes. A volute chamber proved effective to reduce v ortex formation in the outlet. Oil film pattern revealed no flow separ ation on vanes at 5 L/min. Washout flow behind the rotor is essential to prevent thrombus formation and was shown as inward spiral flow with out any stagnation. These data suggested that a combination of visuali zation techniques was useful to analyze various flow conditions, and t he NCVC-1 has excellent flow characteristics with little turbulence an d little flow stagnation, which must be beneficial to low hemolysis an d high antithrombogenicity.