Heat transfer and pressure drop characteristics of inclined elliptical fin tube heat exchanger of varying ellipticity ratio using CFD code

A three-dimensional computational fluid dynamics (CFD) investigation of the friction and heat transfer characteristics of a fin tube heat exchanger having elliptical tubes of various ellipticity ratio and orientation of these tubes to the horizontal are analysed in this study. Air in the transitional regime is considered as the working fluid in this present study. Numerical validation of the predicted results by ANSYS Fluent 15.0 is carried out by comparing the simulated results with the numerical results a obtained by Bhuiyan et al. (2013). Reynold's number at inlet is varied in the range of 1300-1600 and Standard k-omega turbulence model is used for turbulent closure. The ellipticity ratio of the tubes utilized for the analysis ranges between 0.6 and 0.8 and the effect of rotation of these tubes on Colburn factor, friction factor and efficiency index has been analysed. The Colburn factor increased initially reaching a peak, after which it gets lowered with increase in tube inclination. Increase in ellipticity and Reynold's number decreased the Colburn factor. Friction factor varies in direct proportion to tube inclination and ellipticity ratio, whereas it decreases with the increase in Reynold's number. The efficiency index parameter for all the models has been evaluated. (C) 2017 Elsevier Ltd. All rights reserved.