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ASAIO CARDIAC ABSTRACT

PIV REVEALS THE EFFECT OF VANE NUMBER AND ANGEL AS WELL AS FLOW RATE ON PUMP HEMOLYSIS IN CENTRIFUGAL PUMP

Qian, K X1; Feng, Z G1; Yuan, H Y1; Ru, W M1; Zeng, P1

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By hemolysis tests of the impeller pump, the authors have found that the vane number and angle as well as the flow rate have remarkable effect on pump hemolysis. Recent investigation with particle image velocimetry (PIV) technology has demonstrated that the Index of Hemolysis (IH) is directly related to the flow pattern in impeller channels. PIV is a visible approach showing the real flow status in the pump. The different positions of a particle in two PIV pictures taken at 20μs interval decide the velocity value and direction. The velocity of many particles draws the flow pattern of the field. Same pictures are taken at 30° angle of a six-vane impeller with 2, 4 or 6 Umin of flow, respectively; then the pictures at 20° or 40°angle of six-vane impellers, and at 30° angle of five-or seven-vane impellers are taken with 4 Limin flow separately. Results reveal that the 6-vane and 30°-angel impeller with 4 L/min (IH = 0,030) has the best flow field, and no turbulence and no separation can be seen. In other impellers with vane number different from 6 or vane angle different from 30° (IH: 0,120-0,147), or in impellers with 6 vanes and 30° angle but with flow rate different from 4 Limin (IH:0,048-0,082), there is a second flow. It may be concluded that the hemolysis property of a centrifugal pump can be assessed approximately by PIV pictures, which are much easier to take than hemolysis tests.

Copyright © 2004 by the American Society for Artificial Internal Organs