CFD simulation of enhancement of heat transfer in tubes by means of wire coil inserts

Effects of wire coil inserts in enhancement of heat transfer in a smooth tube have been investigated via computational fluid dynamic (CFD) approach. The developed model has been validated by means of experimental data obtained by Garcia et al (Int. J. Heat Mass Transfer 50, 2007). Isothermal pressure drop tests and heat transfer experiments under uniform heat flux conditions have been carried out on three wire coils of different pitch inserted in a smooth tube. To model the turbulent flow, the RNG k  model is employed for computational efficiency and accuracy. The experimental and model results show that wire coils inserted in a smooth tube significantly disturb the flow and remarkably increase heat transfer in which the heat transfer coefficient and friction factor increase with an increase in wire pitch. Numerical results are compared with the experimental data. It is found that the modified turbulence model demonstrated good agreement with experimental results.