Experimental study of thermal hydraulic performance improvement in solar air heater channel with V-shaped porous baffles

Abstract

Experiments have been conducted to determine how several geometrical parameters of V-shaped porous baffles influence flow characteristics and heat transfer in a rectangular channel. Experiments were conducted on geometric parameters, namely, a relative baffle height (e/H) of 0.4–1, a relative baffle pitch (P/e) of 3–6, open area ratio values of 21%–34%, and a single attack angle (a) of 60°. Using Reynolds numbers ranging from 2500 to 12,000, V-shaped porous baffles have been examined. Based on a relative baffle pitch of 5, a relative baffle height of 1, and an open area ratio of 21%, the maximum increases in the Nusselt number (Nu) and friction factor (f) were 2.84 and 7 times, respectively. A maximum value of 1.69 is found at e/H = 0.40, P/e = 6, and b = 34% for the thermo-hydraulic performance parameter. Correlations for (Nu) and (f) are developed as functions of P/e, e/H, and Re.