Experimental Investigation on Heat Transfer Enhancement by Swirl Generators in a Solar Air Heater Duct

Abstract

Experimental investigations on heat transfer enhancement by swirl generators are presented. The thermo hydraulic performance has been evaluated. The experiments were conducted over a wide range of Reynolds number from 993 to 12,034 by employing air (Pr = 0.7) as the working fluid. The major findings of this experimental investigation are that the circular grooved tube with different diameter ratio (h = d/D = 0.04 and 0.06) and pitch ratio (y = p/D = 1.5 and 3.0) perform better than the smooth duct. In evaluation of thermal performance, it is seen that the bluff cylinder of (y = 1.5, h =0.06) are thermodynamically advantageous than the other roughness used. The result is useful for heat exchanger, solar air-heater, etc.