An Experimental Study of Turbulent Heat Transfer in Converging Rectangular Ducts

Abstract

The turbulent heat transfer rate, wall temperature, and pressure distributions in the hydrodynamically and thermally developing region of rectangular converging ducts of taper angle 0, 2-1/2, 5, and 7-1/2 deg have been determined experimentally. The heating condition is such that the top and bottom walls are uniformly heated while the two side walls are unheated. The fluid is air and the experiments cover the Reynolds number range from 2.4 × 104 to 4.8 × 104. The results show that the heat transfer coefficient is increased by the increasing of either the taper angle or the inlet Reynolds number. An empirical correlation between the local Nusselt number and the local Reynolds number was determined.