Correlations for solar air heater duct with dimpled shape roughness elements on absorber plate

Convective heat transfer enhancement in solar air channels

“…Sethi et al [62] conducted an indoor experimental study on the effect of artificial roughness on the Stanton number and pressure drop in an air duct containing dimple-shaped elements arranged in an angular fashion (arc) as roughness elements on a heated plate.…”

Experimental and CFD-based thermal performance prediction of solar air heater provided with right-angle triangular rib as artificial roughness

“…Langewar et al [18] W-shaped rib roughness e/D = 0.033 10 Sethi et al [19] Angular dimple-shaped elements e/D = 0.036 11 Layek et al [20] Chamfered ribs e/D = 0.040 12 Karmare and Tikekar [21] Roughness with metal grit e/D = 0.044 13 Yadav et al [32] Equilateral triangular-sectioned ribs e/D = 0.042 14 Prasad and Saini [45] Transverse wire rib roughness e/D = 0.033 15 Yadav et al [49] Square-sectioned transverse rib e/D = 0.042 16 Present numerical study Right-angle triangular ribs roughness e/D = 0.042 Thus, the heat transfer is found to be strongly dependent on the relative roughness pitch and relative roughness height of right-angle triangular rib along with the variation of Reynolds number. The average Nusselt number decreases with the increase of relative roughness pitch for a fixed value of relative roughness height.…”

“…For the range of parameters investigated, it was found that the highest thermo-hydraulic performance was obtained for W-down ribs as 1.98 and 1.81 for W-up ribs. Sethi et al [19] has investigated the effect of dimple-shaped elements arranged in angular fashion (arc) as roughness elements on the absorber plate of a solar air heater. The maximum enhancement in Nusselt number has been found corresponding to the relative roughness height of 0.036, relative roughness pitch of 10, and arc angle of 60°.…”

A study of heat transfer enhancement in a new solar air heater having circular type turbulators

“…[5] and the obtained results were compared for SAHs having ribbed and smooth duct. Sethi et al [6] conducted experimental study to enhancement of heat transfer in SAHs having dimple shaped roughness. Also, empirical equations for Nusselt number and friction factor were developed and compared with experimental results.…”