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Modelling of cavitation in a high‐intensity agitation cell
Author(s) -
Jose J. K.,
Mmbaga J. P.,
Hayes R. E.,
Xu Z.
Publication year - 2011
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.20612
Subject(s) - cavitation , bubble , mechanics , body orifice , materials science , flow (mathematics) , population , intensity (physics) , volume (thermodynamics) , turbine , thermodynamics , chemistry , mechanical engineering , engineering , physics , demography , quantum mechanics , sociology
Abstract Small‐scale air bubbles, introduced via cavitation, enhance particle flotation in a high‐intensity agitation (HIA) cell. In this work, the local energy dissipation rates which govern the cavitation phenomena in a two‐baffled HIA cell with several different impellers were studied using computational fluid dynamics. The simulation predicts that a 4‐vane flat blade turbine dissipates more power than other turbines tested in the given HIA cell. A cavitation model is used in conjunction with a multiphase mixture model to predict the vapour generation. Cavitating flow is simulated at different RPM, dissolved gas concentration, and temperatures. Predicted volume fraction of vapour showed a strong dependency on operating conditions. For comparative study, cavitation in a pressure driven flow through a constriction is also modelled. A population balance model is used to obtain the bubble size distribution of the generated cavities in an orifice flow. The method can be extended to characterise the bubble size distribution in HIA cells.