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The characteristic dimension in scraped surface heat transfer
Author(s) -
Bott T. R.,
Romero J. J. B.
Publication year - 1966
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.5450440407
Subject(s) - mechanics , heat transfer , heat exchanger , fillet (mechanics) , materials science , tube (container) , inertia , dynamic scraped surface heat exchanger , falling (accident) , heat transfer coefficient , composite material , thermodynamics , classical mechanics , physics , critical heat flux , medicine , environmental health
Previous published work on scraped surface falling film heat exchangers has used the tube diameter as the characteristic dimension. The present investigation confirms that in such equipment the liquid is carried as a fillet, roughly triangular in shape in front of the blades. Using an equivalent diameter based on flow area of the fillet and the length of the are in contact with the transfer surface, a correlation based on earlier results is developed which is independent of tube diameter, except in defining the rotary inertia forces. The refined correlation is:—\documentclass{article}\pagestyle{empty}\begin{document}$$ N_{Nu} = 0.0023 N_{Re}^{0.52} N_{Re}^{0.57}N_{Pr}(L / De)^{-0.44} \pi^{0.81} $$\end{document}