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 transfer enhancement in laminar flow of non-Newtonian fluids, aqueous Carbopol-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 have a polymer concentration range of 1000-2000 wppm. It is shown that the enhanced heat transfer behavior of the Carbopol solutions within low Reynolds number range is different from that within relatively high Reynolds number range. There exists a limiting polymer concentration, C-max, at which the non-Newtonian fluid possesses the maximum ability to enhance heat transfer. If the polymer concentration becomes too high, the minimum Reynolds number required to enhance heat transfer increases with the increasing polymer concentration.