Thermal performance enhancement in solar air heater channel with periodically V-shaped baffles

Abstract

The research paper presents a study on thermal performance enhancement in a rectangular channel heat exchanger mounted with periodically V-shaped baffles. The channel has an aspect ratio (width to height ratio), AR=10 and height, H=30 mm while baffle characteristics are the baffle to channel height ratio, e/H=0.2, 0.3 and 0.4; the baffle pitch to channel height ratio, PR=P/H=2 and 2.67; the attack angle (α) of 30° relative to the flow direction. The experiment has been conducted by varying air flow velocity in order to adjust Reynolds number range from 5000 to 25,000. The upper wall of the channel is uniformly heated as a constant heat flux while the rests are covered with thermal insulations to reduce heat loss to surroundings. The effects of the baffles on Nusselt number and friction factor have been examined. The overall performance of tested baffled channel is evaluated to obtain the degree of heat transfer enhancement and friction factor induced by baffles with respect to the smooth channel under similar flow conditions.