Abstract
Abstract The fully established friction factors and heat transfer coefficients of the turbulent flow of viscoelastic fluids in a 5:1 rectangular duct were measured experimentally. The bottom wall, one of the longer sides of the duct, was heated by passing direct electric current through it, yielding constant peripheral wall temperature and constant heat input per unit length along the bottom wall. The other surfaces were adiabatic. The test section is 150 hydraulic diameters long. The fluids studied were aqueous solutions of three different polymers (potyacrylamide, polyethyleneoxide, and hydroxyethylcellulose). The measured turbulent asymptotic friction factors are in agreement with the values reported in the literature. However, the fully established turbulent Nusselt values do not appear to have reached the asymptotic limiting value for heat transfer. The available empirical j-factor correlation for circular pipes does not predict the present experimental values measured in a rectangular channel with only one wall being heated.
Published Version
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