LAMINAR HEAT-TRANSFER IN SQUARE DUCT FLOW OF AQUEOUS CMC SOLUTIONS

Experimental studies on the laminar heat transfer of 4000 wppm and 800 0 wppm aqueous carboxymethylcellulose(CMC) solutions in a top-wall hea ted square duct have been carried out. The square duct is 240 cm long and its hydraulic diameter is 0.4 cm. Results show that the aqueous CM C solutions are good candidates for laminar heat transfer enhancement in a non-circular duct. Under the examined conditions, the enhanced lo cal heat transfer along the whole duct wall can be characterized by a two-zone model with a Newtonian heat transfer section followed by a vi scoelastic heat transfer section. The fully developed heat transfer of the aqueous CMC solutions can be well determined by linear correlatio ns with the Kozicki generalized Reynolds number.