INT. C~. HEAT MASS TRANSFER 0735-1933/85 $3.00 + .00 Vol. 12, pp. 483-490, 1985 ~_r~-orL Press Ltd. Printed in the United States HEAT TRANSFER PERFORMANCE OF AQUEOUS POLYACRYLAMIDE SOLUTIONS IN TURBULENT FLOW THROUGH A RECTANGULAR CHANNEL M. Kostic I and J.P. Hartnett 2 1 University of Belgrade, Yugoslavia 2 University of Illinois at Chicago (C~t,~nicated by J.P. Hartnett and W.J. Minkowycz) ABSTRACT A good estimate of the friction factor and dimensionless heat transfer coefficient, JH, of an aqueous polyacrylamide solution in turbulent flow through a 2:1 rectangular duet may be obtained from the available relation for such solutions in turbulent pipe flow. Introduction It is well known that the addition of small amounts of certain high molecular weight polymers to water results in a decrease of the pressure drop and heat transfer for a fixed flow rate of the aqueous polymer solution in turbulent pipe flow [l-b]. Accordingly, the friction factor and the dimensionless heat transfer coefficient of such aqueous polymer solutions are lower than the corresponding values for water flowing alone when compared at the same Reynolds number. In general, the friction factor and dimensionless heat transfer decrease with an increase of polymer concentration up to asymptotic values, beyond which further increases in polymer concentration have no effect on the friction factor and heat transfer. The asymptotic friction factor is reached at a lower polymer concentration than that associated with the asymptotic heat transfer. Virk [1] is credited with the finding that there is an asymptotic friction factor, often called Virk's maximum drag reduction asymptote. It is given by the relationship: 483