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Abstract:
A
pulsatile axial pump and a pulsatile centrifugal pump are developed. The
pulsatile flow of impeller pump is discussed. In the pulsatile axial
pump, the impeller reciprocates axially and rotates simultaneously. The
reciprocation is driven by a pneumatic device and the rotation by a DC
motor. For 5.3 kPa pulsatility of pressure, about 50 mm axial
reciprocating amplitude of the impeller is desirable. In order to reduce
the axial amplitude, the pump inlet and the impeller both have
cone-shaped heads, and the gap between the impeller and the inlet pipe
changes only 2 mm, namely, the impeller reciprocates 2 mm, a pressure
pulsatility of 5.3 kPa can be produced. As the impeller rotates with
constant speed, low turbulence in axial pulsatile pump may be expected.
In centrifugal pulsatile pump, the impeller changes its rotating speed
periodically, the turbulence is reduced by designing an impeller with
twisted vanes which enable the blood flow to change its direction rather
than its magnitude during the periodic change of the rotating speed. In
this way , a pulsatile flow is produced and the turbulence has been
minimized. Compared to the axial pulsatile pump, the centrifugal
pulsatile pump needs only one driver and thus has more reality for
application. The centrifugal pulsatile pump is used in animal
experiments. The pump assisted the circulation of the calves for several
months without harm to the blood elements and the organ functions of the
experimental animal. The experiments demonstrated furthermore that the
pulsatile impeller pump is the most efficient assist pump for heart
recovery.
Key words:
Pulsatile
flow Impeller pump Centrifugal pump Turbulence
shearing stress Hemolysis Axial pump
CLC No: R318.11
国家“九五”攻关项目及国家自然科学基金资助项目. Received 20000321,
received in revised form 20000928
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