Heat Transfer Augmentation by Multijet Air Impingement on Dimpled Heat Sink

Abstract

Experimental investigation of heat transfer by multiple jets of air on the dimpled surface has been carried out. The experiment is performed by using 4x4 array of nozzle. Three different types of heat sinks of Al with dimensions 80x80x5 mm are used by varying dimple depths of spherical diameters 6mm and 8mm.Various iterations are performed using Reynolds numbers from 6000,8000,10000 and 12000 and varying Z/D ratios from 5 to 6. After doing various iterations using Nusselt number, Reynolds number and Z/D ratios it was found that various parameters which gives heat transfer augmentation to spherical cavity dimples with 6 mm diameter gives maximum heat transfer with all three different heat sinks. Jet impingement cooling technique is utilized when high rate of heat transfer are required. Compared to all other surfaces dimples has simple geometry easy to manufacture and gives more turbulence with low pressure penalty.