Heat transfer analysis of a non-Newtonian fluid flowing through a circular tube with twisted tape inserts

In this paper, the moment and heat transfers of a non-Newtonian fluid flowing in steady laminar regime through a circular tube with a twisted tape at constant wall temperature is studied using CFD. The effect of different twist ratios of the tape on the convective heat transfer and the pressure drop are investigated over the Reynolds number range of 0.2-600. It was found that a twisted tape induces a swirling flow, which increases the velocity gradient at the tube wall and consequently generates an enhancement in heat transfer. Data reduction is applied to CFD data; and it is found a good agreement between the calculated Reynolds and Fanning friction numbers and the theoretical relationship (f = 16/Re). A novel formulation for evaluating the thermo-hydraulic performance was developed. The results indicate that the thermo-hydraulic performance increases when the twist ratio decreases and the Reynolds number increases. (C) 2015 Elsevier Ltd. All rights reserved.