FORCED-CONVECTION HEAT TRANSFER FROM THE BOTTOM OF TRENCHES WITH RECTANGULAR OR INCLINED WALLS

Abstract

Abstract Experimental results are presented on the heat transfer from the bottom of rectangular and trapezoidal trenches streamlined by a turbulent flow. Peculiarities of heat transfer are outlined upon varying both the width and height of rectangular trenches and the width of trenches with inclined walls. The mean heat transfer at the trench bottom is found to be determined, depending on the trench's geometry, either by turbulent diffitsional transfer, Nu ˜Re⅔ H or turbulent boundary layer, Nu ˜ Re0.8 H. A change from 45° up to 90° in the inclination angle of walls influences heat transfer in a complicated manner: at α = 60° the heat transfer is intensified, while at a α= 45° a delay in the transition from laminar to turbulent heat transfer takes place.