Hindawi Publishing Corporation e Scientific World Journal Volume 2013, Article ID 492762, 8 pages http://dx.doi.org/10.1155/2013/492762 Research Article Numerical Investigation of Heat Transfer and Friction Factor Characteristics in a Circular Tube Fitted with V-Cut Twisted Tape Inserts Sami D. Salman, 1,2 Abdul Amir H. Kadhum, 1 Mohd S. Takriff, 1 and Abu Bakar Mohamad 1 1 Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia 2 Biochemical Engineering Department, Al-Khwarizmi College of Engineering, University of Baghdad, Baghdad 47024, Iraq Correspondence should be addressed to Sami D. Salman; sami.albayati@gmail.com Received 29 June 2013; Accepted 28 July 2013 Academic Editors: N. H. Afgan and A. Greco Copyright © 2013 Sami D. Salman et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Numerical investigation of the heat transfer and friction factor characteristics of a circular fitted with V-cut twisted tape (VCT) insert with twist ratio ( = 2.93) and different cut depths ( = 0.5, 1, and 1.5 cm) were studied for laminar flow using CFD package (FLUENT-6.3.26). e 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 ( = 2.93, 3.91, 4.89) were also studied for comparison. e 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. e results also revealed that the V-cut twisted tape with twist ratio  = 2.93 and cut depth  = 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-leſt 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. 1. Introduction Heat exchangers with the convective heat transfer are widely used in many engineering applications. Enhancement of heat transfer in all types of thermotechnical apparatus is of great significance for the industry. Besides the savings of primary energy, it also leads to a reduction in size and weight. In general, heat transfer enhancement techniques can be divided into two categories: (1) active techniques which need external power source and (2) passive techniques which do not need external power source. Several experimental studies on heat augmentation techniques using twisted tape as passive tech- nique have been reported in the literature [1–15]. ereaſter and due to advances in computer hardware and soſtware and consequent increase in calculation speed, the CFD modeling technique was developed as a powerful and effective tool for better understanding of the complex hydrodynamics in many industrial processes. 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. ey 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. Sivashanmugam et al. [17] presented the modeling of heat transfer augmentation in a circular tube fitted with a helical twist insert in a laminar and turbulent flow using CFD. Jayakumar et al. [18] offered a comparison study of CFD simulations to experiment on convective heat transfer in double pipe helical heat exchanger and developed an empirical correlation for estimation of the inner heat transfer coefficient of a helical coil. 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