Performance investigation of heat exchanger tube fitted with hyperbolic-cut twisted tape in turbulent flow

Abstract

Investigation of Nusselt number, friction factor, and thermo-hydraulic performance characteristics in turbulent flow tube with hyperbolic-cut twisted tape (HCTT) has been reported using ANSYS Fluent 19.2. The effect of hyperbolic-cut ratios (0.3 [Formula: see text] b/c [Formula: see text] 1.2) and non-dimensional cut width (0.56 [Formula: see text] c/w [Formula: see text] 0.89) are inspected for 10000 [Formula: see text] Re [Formula: see text] 22000 in a tube of 20 mm diameter. In the present study, the comparison is made among all available turbulence models, and k- [Formula: see text] RNG turbulence model is found to be reliable. The present turbulence model is also compared with existing experimental data. The tube equipped with HCTT provides swirling of flow and additional flow around the cuts. This induced flow enables heat transfer and pressure drop between the core and near-wall region of the tube. The presence of hyperbolic-cut leads to better mixing and centrifugal motion of near-wall fluid, which has a remarkable effect on heat transfer and friction factor characteristics in the fluid region. The Nusselt number, friction factor, and thermo-hydraulic performance of HCTT are enhanced up to 12.16%, 22.54%, and 7.36% compared to TT, respectively. The performance of the present geometry is compared with twisted tape and is found to be best for non-dimensional cut width of 0.67 for all the values of Re 10000–22000. The performance of the proposed geometry has also been compared with existing works, and performance is found to be excellent for Re [Formula: see text] 16000. Further, correlations have been developed to predict the Nusselt number, friction factor, and thermo-hydraulic performance. This numerical investigation could be expected to be helpful for engineers and researchers in designing modern heat exchangers.