Abstract

The principle of heat transfer enhancement has been widely applied in various fields, including electronic cooling—particularly in central processing units (CPUs)—heat exchanger units, gas turbine blade cooling, biomedical devices, and nuclear power plants. In the present study, a series of experiments was conducted to investigate free convection heat transfer in a horizontal rectangular duct. Three flat plates were tested: the first was a smooth plate without grooves, while the second and third had V-grooves inclined at 30° and 60°, respectively, relative to the horizontal. The objective was to examine the effect of varying heat flux rates, ranging from 148.6 to 1248 W/m², on the heat transfer coefficient and Nusselt number for both smooth and V-grooved plates. The results indicated that the V-grooved plate inclined at 30° significantly enhanced the heat transfer rate with increasing heat flux. Empirical correlations for the mean Nusselt number as a function of the Rayleigh number were derived for each of the plates tested.

Keywords

Heat transfer enhancement, Free convection, V-grooved plates, Nusselt number, Rectangular duct.

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