Heat and mass transfer from a surface to a stream of fluid are governed by Fourier’s
law and Fick’s law respectively. These are mathematical manifestations of the process
of diffusion. In the realm of transport processes, the mathematical equations describing
the two phenomena can become analogous under certain assumptions and boundary
From an engineering perspective, it is difficult to measure heat transfer coefficients in
separated flows because of high spatial thermal gradients and the intrusive nature of the
various techniques. The analogous mass transfer measurement using the naphthalene
sublimation technique, on the other hand, overcomes these challenges and presents
significant advantages of speed, economy, better resolution and accuracy over its thermal
counter-part. However, the diffusion rates of napthalene and heat into a stream of air
are different. So, the physical and mathematical similarity between the two processes
can be utlized effectively only when the analogy factor (F=Nu/Sh) is determined.
This study investigates the heat/mass transfer analogy in a turbulent separated flow
behind a backward facing step. The heat (Nu) and mass (Sh) transfer measurements
were made using the thermal boundary layer technique and the naphthalene sublimation
technique respectively under identical flow conditions. Analogous boundary conditions
of constant temperature and constant concentration were imposed on the active surface
in the study which is the recirculation-reattachment region behind the backward facing
University of Minnesota M.S. thesis. December 2010. Major: Mechanical Engineering. Advisor: Dr. Richard J. Goldstein. 1 computer file (PDF); xv, 105 pages, appendices A-B. Ill. (some col.)
Experimental verification of heat/Mass transfer analogy in turbulent separated flow behind a backward facing step..
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