Experimental Analysis of Heat Transfer Enhancement over Dimpled Surface on One Side of Plate

Abstract

Many researchers perform enhancement over various dimpled surface. Dimples are used on the surface of internal flow passages because they produce substantial heat transfer augmentation. This work is concerned with experimental investigation of the forced convection heat transfer over the dimpled surface. The experimental analysis objective is to find out the heat transfer and air flow distribution on dimpled surfaces and all the results obtained are compared with those from a flat surface. The varying parameters were i) Inline dimples on the plate i.e. spherical and conical ii) Heat input and iii)Dimple density on the plate. Heat transfer coefficients and Nusselt number were measured in a channel with one side dimpled surface. The spherical and conical type dimples were fabricated, and the diameter and the depth of dimple were 6 mm and 3 mm, respectively. Two dimple arrangement of inline spherical and conical were tested. The Reynolds number based on the channel hydraulic diameter was varied from 2000 to 8500.Study shown that increase with Reynolds number, thermal performance also increases. With the inline dimple arrangement for spherical and conical arrangements, the heat transfer coefficients, Nusselt number and the thermal performance factors were higher for the conical inline arrangement and also pressure drop penalties smaller than with other types of heat augmentation.