Mass and heat transfer in a turbulent non-newtonian boundary layer

Abstract

Using the three-zone model proposed by Levich, a new theoretical expression for turbulent heat and mass transport in inelastic non-Newtonian liquids has been proposed. This new model, $\text{j}\text{= 0.075}\text{n}{}^{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}\text{(}\text{K}\text{/g9)}{}^{\mathrm{<mtext>-2</mtext><mtext>3</mtext><mtext>n</mtext>}}\text{v}{}_{\mathrm{o}}\text{(4−}\text{n}\text{)}\text{3}\text{n}\text{(}\text{C}{}_{\mathrm{o}}\text{− C}{}_{\mathrm{b}}\text{)}$ which has no adjustable parameters, has been derived under the assumption that the Schmidt number is fairly high as is the case in viscous polymer systems and fermentation broths. The predictive capability of this equation was tested in this work for flow situations for which the friction velocity v_o is known: tubular non-Newtonian heat transfer and turbulent non-Newtonian mass transfer from a spinning disk. The excellent agreement between the available experimental data and the predictions of our model gives confidence to using the above model for that the heat and/or mass transfer rate increases if the pseudoplastic anomaly increases and that this enhancement is more pronounced in turbulent regime than it is under laminar conditions of flow.