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Analytical Investigation of Leakage Flow in Disk Clearance of a Magnetically Suspended Centrifugal Impeller
Author(s) -
Chan W.K.,
Akamatsu T.,
Li H.D.
Publication year - 2000
Publication title -
artificial organs
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.684
H-Index - 76
eISSN - 1525-1594
pISSN - 0160-564X
DOI - 10.1046/j.1525-1594.2000.06507.x
Subject(s) - impeller , mechanics , shear stress , rotational speed , slip factor , centrifugal pump , leakage (economics) , materials science , axial compressor , radius , volumetric flow rate , flow (mathematics) , physics , classical mechanics , thermodynamics , gas compressor , computer security , computer science , economics , macroeconomics
Leakage flow through the disk clearance of a magnetically suspended centrifugal blood pump is essential for a good washout. An analytical approach, based on the theory of lubrication, is used to predict the leakage volume flow rate, nondimensional radial velocity, nondimensional mean pressure distribution, and comparative shear stress distribution for different disk clearance geometry under varying rotational speeds. The results showed that nondimensional mean pressure distribution and nondimensional radial velocity distribution along the clearance are independent of rotational speed. The flow through the gap depends on a nondimensional parameter S that denotes the ratio of centrifugal forces to the head generating capability of the impeller. It was found that an impeller having a lower S has less possibility of flow reversals in the gap, and gap with maximum height at the outside radius also is more susceptible to flow reversals at the impeller surface. The comparative shear stress within the gap reveals that, in general, the scalar stress is below 500 N/m 2 .