A Numerical Study of the Flow and Heat Transfer Characteristics of Outward Convex Corrugated Tubes With Twisted Tape Insert

Abstract

This work presents a mathematical model for simulating the swirling flow in an outward convex corrugated tube with twistedtape insert (CT). The synergistic effect on the flow, heat transfer, and friction loss behaviors between the surfacebased and fluidbased enhancements is numerically investigated. Renormalized group (RNG) kخµ turbulence model applied in our paper is verified by comparing with experimental results investigated by Manglik and Bergles. Comparisons of the CT and smooth tube with twistedtape insert (ST) plots are confirmed to investigate the performance differences between them. When comparing the performance of the CT against the ST, the maximum ratio of Nusselt number (Nuc/Nus), ratio of friction factor (f/fs), and overall heat transfer performance (خ·) values realized in the CT are 1.36, 1.53, and 1.15 times higher, respectively, than the maximum values for those same variables in the ST.