Effect of roughness width ratio in discrete Multi v-shaped rib roughness on thermo-hydraulic performance of solar air heater

Abstract

The artificial roughness on underside of heated surface has been found to be effective technique to improve thermo hydraulic performance of solar air heater duct. In progression to the previous researches, the present study discloses the effect of discrete Multi v-rib on heat transfer and friction in a flow through artificially roughened solar air heater duct. The experimentations were performed to collect the data on heat transfer and friction by varying the Reynolds number (Re) between 2,000 and 20,000, relative width ratio (W/w) from 1 to 10, for the fixed values of relative gap distance Gd/Lv = 0.69, relative gap width g/e = 1.0, relative roughness pitch P/e = 8, relative roughness height e/D = 0.043 and angle of attack α = 60°. The present roughness geometry with relative width ratio (W/w) of 6.0 corresponding to flow Re of 20,000 yields the best thermo hydraulic performance.