ENHANCEMENT OF HEAT TRANSFER OF SOLAR AIR HEATER ROUGHENED WITH CIRCULAR TRANSVERSE RIB

Abstract: An experimental investigation of the effect of geometrical parameters of circular transverse ribs on heat transfer of rectangular duct with heated plate having rib roughness on its underside have been reported. The range of parameters for this study has been decided on the basis of practical considerations of the system and operating conditions of solar air heaters. The experimental investigation encompassed the Reynolds number (Re) range from 2564 to 6206; relative roughness pitch (P/e) of 8, angle of attack (α) of 90° and relative roughness height (e/Dh) is 0.047. The thermal efficiency of roughened duct is observed to be 5%-9% more as compare to the smooth duct. The thermal efficiency is increased with increasing the value of Reynolds number.

Keywords: Solar air heaters, heat transfer, thermal efficiency, Reynolds number.