| Popis: |
Influence of the dual twisted tapes (DTs) on the heat transfer enhancement in a circular tube is reported. The effects of twist ratio (y/w = 2.0, 3.0 and 4.0) on the heat transfer rate, friction factor, and thermal performance factor in a tube under constant wall heat flux were investigated in turbulent regions. Computations, based on a finite volume method, and the SIMPLE algorithm, were carried out by QUICK schemes. From the numerical results, heat transfer rate and pressure loss increased as twist ratio of tape (y/w) decreased. Based on the same pumping power consumption, the optimum thermal performance was achieved by the use of the tapes with twist ratio of 3.0. In addition, the predictions of flow-thermal phenomena (streamline, velocity vector, TKE and local Nusselt number) are also described. |
