Published Paper Details:

The objective of this paper to study of heat and fluid flow processes in an artificially roughened solar air heater. Artificially roughness introduce under side of absorber plate of solar air heater in the form of small transverse wire ribs. Solar air heater is a type of heat exchanger which convert solar radiation into thermal (heat) energy. Thermal performance of solar air heater has been found very low due to low convective heat transfer coefficient from the absorber plate to the air. Use of artificially roughness is an effective technique to enhance the rate of heat transfer. This investigation performed on circular section with different values of Reynold numbers range from 3800-18000. Reynold no, relative pitch height (p/e) and relative roughness height (e/d) are chosen as design variables. Two-dimensional CFD simulation is perform using the ANSYS FLUENT version 12.1 .The renormalization group (RNG) k-e model is selected as the most appropriate once. Comparing the results obtain by our study of CFD approach of circularsections with different rib pitch (p) and roughness heights(e)of Reynold number range 3800-18000.The effect of pitch, rib height, relative roughness height(e/D), relative roughness pitch(p/e) on Nusselt number and friction factor have been discussed and the result compared with rough duct and smooth duct under simpler flow conditions. Nusselt enhancement factor and friction enhancement factor of roughed solar air heater have been optimized the considering the thermo-hydraulic performance. Maximum Thermo-hydraulic performance have been found 1.72 of circular transverse wire rib section at p=10 mm, e=1.4 mm, and e/D=0.042.Hence these values are chose best design dimensions of circular section.