EXPERIMENTAL INVESTIGATION OF THE LAMINAR-FLOW HEAT-TRANSFER ENHANCEMENT IN A SMALL-SCALE SQUARE DUCT WITH AQUEOUS CARBOPOL SOLUTIONS

This paper presents results of an experimental study on the heat trans fer enhancement in laminar flow of non-Newtonian fluids, aqueous Carbo pol-934 solutions through a small-scale square duct The square duct is a top-wall heated configuration with a hydraulic diameter of 0.4 cm. The aqueous Carbopol solutions examined are those neutralized, and hav e a polymer concentration range of 1000-2000 wppm. It is shown that th e enhanced heat transfer behavior of the Carbopol solutions within low Reynolds number range is different from that within relatively high R eynolds number range. There exists a limiting polymer concentration, C -max, at which the non-Newtonian fluid possesses the maximum ability t o enhance heat transfer. If the polymer concentration becomes too high , the minimum Reynolds number required to enhance heat transfer increa ses with the increasing polymer concentration.