Experimental study of heat transfer and frictional characteristics of impinging jet solar air heater with wire-mesh attached to the absorber plate
Chinmaya Mund, Sushil Kumar Rathore, Ranjit Kumar Sahoo
Abstract
This study revolves around improving the thermal performance of impinging jet solar air heater (IJSAH) by using wire mesh of three different sizes. The wire mesh sizes were 0.5 × 0.5 , 1.5 × 1.5 , and 3 × 3 inches with nozzle diameter (Dj) equal to 3 and 6 mm and Reynolds number (Re) ranging from 4913 to 13103. The variation of Nusselt number (Nu), friction factor (f), thermo-hydraulic performance parameter (THPP), and effective efficiency ( η e f f ) were evaluated for varying Re. Maximum Nu was developed for case 3 and equalled 109.86, which was 7.3 % and 246 % higher than a smooth IJSAH and flat plate solar air heater (FPSAH), respectively. The minimum friction factor attained equated to 0.0314 for case 2 at Re = 13103. Maximum THPP attained by the setup equalled 1.78 for case 4, having Dj = 6 mm. The THPP attained by case 4 across the range of Re was on an average 9.15 % higher when compared to smooth IJSAH with Dj = 3 mm. Additionally, the system achieved maximum η e f f of 0.53695 at Re = 4913 for case 4. Finally, it was recommended to use a wire mesh having a mesh size equal to 1.5 × 1.5 inch with Dj = 6 mm for optimum performance.