Laminar heat transfer to time - independent non - newtonian fluid in tubes

Abstract

Heat transfer characteristics for the heating of the dilute, solutions of different types of Cellofas in straight tubes are studied ,numerically in laminar condition with constant wall temperature considering viscous dissipation. The scope of this study is limited to numerical prediction of velocity profile, temperature profile and the rate of heat transfer at steady fully developed condition. "TEACH-T", a general computer program has been used for this purpose. After sufficient testing against bench-mark experimental and analytical data, the computer program was used for the prediction of flow and heat transfer data. The present study is confined to a tube of fixed diameter 17.4 mm. Power law model describes the flow behaviour of the fluids and the fluid consistency, K is temperature dependent. To study the effect of heating on velocity profile, temperature profile and the rate of heat transfer, three different temperature ratio T./T., namely, 1.068, 1.13 and 1.233 were considered. Present study indicates that velocity profile becomes flatter with the increase of pseudoplasticity and temperature ratio, The • effect of pseudopastici ty on temperature profi Ie is small but the effect of temperature ratio is significant. Effect of pseudoplasticity and viscous dissipation on heat transfer rates are interrelated. This combined effect is small because the fluids considered do not have large values for consistency, K.