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An experimental study of the effects of wall conductivity, non-uniform magnetic fields and variable-area ducts on liquid metal flows at high Hartmann number. Part 1. Ducts with non-conducting walls

Published online by Cambridge University Press:  19 April 2006

Richard J. Holroyd
Richard J. Holroyd
Affiliation:
Department of Engineering, University of Cambridge Present address: Department of Engineering Science, University of Oxford.
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Abstract

The results are presented of an experimental investigation of the flow of mercury along straight, circular and rectangular non-conducting ducts situated in a magnetic field that is uniform except over a short length of the duct where its value decreases by 50%. Magnitudes of the field strength and mean velocity are such that the Hartmann number M is large, the interaction parameter N ≈ M½ and the magnetic Reynolds number Rm [Lt ] 1. In all but one respect this is the prototype problem analysed by Holroyd & Walker (1978): their analysis required that N [Gt ] M½.

Distributions of pressure, electric potential and velocity are measured, the latter by hot-film probes. Qualitative agreement with the theoretical predictions is obtained in so far as a pressure drop of O(duct radius × fully-developed flow pressure gradient × M½) occurs over the non-uniform field region and, in the circular duct, the fluid can be seen to migrate towards the centre of the duct upstream and downstream of the non-uniform field region but in that region this tendency is reversed.

Similar effects appear to occur in the rectangular duct.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 93 , Issue 4 , 29 August 1979 , pp. 609 - 630
Copyright
© 1979 Cambridge University Press

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