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Turbulent entrainment into inert and reacting multiphase plumes

Published online by Cambridge University Press:  15 July 2011

SEAN T. McHUGH
Affiliation:
Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, UK
SILVANA S. S. CARDOSO*
Affiliation:
Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, UK
*
Email address for correspondence: sssc1@cam.ac.uk

Abstract

Theoretical predictions and experimental results for turbulent entrainment in inert and reacting, multiphase plumes are presented. It is shown that in an inert, pure plume, the entrainment coefficient is approximately constant with downstream distance. In a reacting plume, in which buoyancy is depleted by chemical reaction, the entrainment coefficient decreases strongly with distance from the source owing mainly to a decrease in the Richardson number. The effect on entrainment of the drift in the velocity and buoyancy distributions in the radial direction, i.e. the similarity drift introduced by Kaminski, Tait & Carazzo (J. Fluid Mech., vol. 526, 2005, pp. 361–76), is found to increase with downstream distance and with the reaction rate but, on laboratory-scale experiments, remains small compared to the contribution to entrainment from the turbulent stresses and buoyancy.

Type
Papers
Copyright
Copyright © Cambridge University Press 2011

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