Abstract
Numerical investigation of the heat transfer and friction factor characteristics of a circular fitted with V-cut twisted tape (VCT) insert with twist ratio (y = 2.93) and different cut depths (w = 0.5, 1, and 1.5 cm) were studied for laminar flow using CFD package (FLUENT-6.3.26). The data obtained from plain tube were verified with the literature correlation to ensure the validation of simulation results. Classical twisted tape (CTT) with different twist ratios (y = 2.93, 3.91, 4.89) were also studied for comparison. The results show that the enhancement of heat transfer rate induced by the classical and V-cut twisted tape inserts increases with the Reynolds number and decreases with twist ratio. The results also revealed that the V-cut twisted tape with twist ratio y = 2.93 and cut depth w = 0.5 cm offered higher heat transfer rate with significant increases in friction factor than other tapes. In addition the results of V-cut twist tape compared with experimental and simulated data of right-left helical tape inserts (RLT), it is found that the V-cut twist tape offered better thermal contact between the surface and the fluid which ultimately leads to a high heat transfer coefficient. Consequently, 107% of maximum heat transfer was obtained by using this configuration.
Highlights
Heat exchangers with the convective heat transfer are widely used in many engineering applications
It is observed that the accuracy of the result increases with increase in mesh number and the accuracy became constant around 292655 cells for plain tube and tube fitted with classical twisted tape inserts, and final computational fluid dynamics (CFD) simulations were done at this cell
(i) The values of the Nusselt number and friction factor for the tube with V-cut twisted tape are noticeably higher than the values for the plain tube and tube equipped with classical twisted tapes as well
Summary
Heat exchangers with the convective heat transfer are widely used in many engineering applications. Kumar et al [16] studied the hydrodynamics and heat transfer characteristics of tube in the form of the helical heat exchanger at a pilot plant scale fitted with semicircular plate in annuals area using a commercial CFD package to predict the flow and thermal properties in a tube of the helical heat exchanger. They found that the results of the simulated data of the Nusselt number and friction factor in the inner and outer tubes coincide with experimental data. Lei et al [19] conducted the hydrodynamics and heat transfer study on heat exchanger with a single-segment baffle, single-layer helical baffle, and two-layer helical baffle experimentally as
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