Heat transfer at an upstream-facing surface washed by fluid en route to an aperture in the surface

Ephraim M Sparrow, U. Gurdal

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Forced convection heat transfer coefficients were measured at a plane surface pierced by an aperture (or tube inlet) of diameter d into which fluid flows from a large upstream space. Heat transfer effects were confined to a portion of the surface contained within an annulus of outer diameter D which surrounds the aperture. The experiments were carried out for several values of the d/D ratio ranging from 1/6 to 1/14.4, and for each fixed d/D the Reynolds number was varied parametrically over a range that spanned a factor of five. Dimensional analysis led to a Reynolds number Re involving the rate of mass flow through the aperture and the outer diameter D of the thermally active region. The end result of the dimensional analysis indicated that for a fixed Prandtl number, the Nusselt number could depend on both Re and d/D. When the Nusselt number data for all cases were brought together on a single graph which spanned more than a decade in Reynolds number, no dependence on d/D was observed. The data are very well correlated by the equation Nu=2.88 Re0.452 Pr1/3 over the range from Re=200 to 3000. It was also found that the average rate of heat transfer per unit area drops off sharply as the outer diameter of the thermally active annular region increases.

Original languageEnglish (US)
Pages (from-to)851-857
Number of pages7
JournalInternational Journal of Heat and Mass Transfer
Issue number5
StatePublished - May 1981


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