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Axial dispersion for turbulent flow with a large radial heat flux
Author(s) -
Beckman Lawrence V.,
Law Victor J.,
Bailey Raymond V.,
Von Rosenberg Dale U.
Publication year - 1990
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690360411
Subject(s) - taylor dispersion , mechanics , turbulence , heat exchanger , heat transfer coefficient , dispersion (optics) , thermodynamics , tube (container) , mass transfer , work (physics) , heat transfer , pipe flow , mass transfer coefficient , chemistry , heat flux , physics , materials science , optics , diffusion , composite material
In 1954, G. I. Taylor derived an expression for an apparent axial dispersion coefficient for mass transfer in turbulent flow under the assumption of no mass transport between the tube wall and the fluid inside the tube. Taylor's expression has been verified in a number of experimental efforts for both mass and heat transfer. This work extends the results of Taylor to the case where there is a significant transport of heat from the tube wall to the fluid in the tube, such as in a double‐pipe heat exchanger. Using an analysis similar to Taylor's, it is shown that the apparent axial dispersion coefficient is about one order of magnitude larger when a large radial gradient is present. Experimental data on a double‐pipe heat exchanger show significantly improved correspondence with a dispersion‐based model of the system when the larger dispersion coefficients are used.