Convective Heat Transfer in a Moving Bed with Special Reference to Melting


Previous workers have been unable to correlate data on forced convection melting of metals or organic solids in packed beds in the accepted manner of heat transfer factor or Nusselt number against Reynolds number. it was recognised that melting in a tower furnace was restricted to a short zone at the bottom so, to simplify the problem, Akers (2) simulated the upper zone under moving bed conditions. His heat transfer coefficients and those of Norton 26) were as much as an order of magnitude less than those obtained by other workers using fixed beds. It was considered that this discrepancy had to be explained before proceeding to the analysis of melting beds. The present work has shown that it stemmed from two main causes: dislocations of the bed near the walls permitted bypassing of the fluid in the regions of high voidage; with long beds the terminal temperature differences tended to zero so measurement errors became unusually significant. By operation with vessel to particle diameter ratios not less than 13 and by selection of conditions to prevent small terminal differences, data have been obtained for 6, 9 and 12 mm diameter glass ballotini heated by air which are in close agreement with published fixed bed results. They are correlated by: Nu = 0.183 x Re0.834 for 95<Re<1662. A previous model of adiabatic moving bed heat transfer with intra-particle temperature distribution has been extended to the non-adiabatic case. <A new digital computer approach to solution of the model has showm that a previous hybrid-analogue computer method was unstable. Digital numerical integration has been used for analysis of experimental results and for prediction of general parameters which will greatly simplify the design of moving beds.

Divisions: College of Engineering & Physical Sciences > School of Infrastructure and Sustainable Engineering > Chemical Engineering & Applied Chemistry
Additional Information: Copyright © Wilson, 1972. W.R. Wilson asserts their moral right to be identified as the author of this thesis. This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with its author and that no quotation from the thesis and no information derived from it may be published without appropriate permission or acknowledgement. If you have discovered material in Aston Publications Explorer which is unlawful e.g. breaches copyright, (either yours or that of a third party) or any other law, including but not limited to those relating to patent, trademark, confidentiality, data protection, obscenity, defamation, libel, then please read our Takedown Policy and contact the service immediately
Institution: Aston University
Uncontrolled Keywords: Convective heat transfer,moving bed,melting
Last Modified: 08 Dec 2023 08:02
Date Deposited: 21 Nov 2010 10:07
Completed Date: 1972
Authors: Wilson, William R.

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