Study of heat transfer enhancement through the non-circular ducts using three dimensional numerical investigations and their comparisons

Abstract

Abstract The present study numerically surveyed fluid characteristics such as friction factor and heat transfer through the different geometry of twisted ducts. A three-dimensional analysis is performed for the Reynolds number of 100-50000 for the air that acts as a working fluid and a uniform wall temperature boundary case is studied numerically throughout the simulation of ducts. Numerical results of this present study are validated against the experimental results. Heat transfer improvements are made over the hexagonally twisted channels, straight square duct and clockwise-counterclockwise (CW-CCW) twisted square channels. Twist ratios of 7 · 5, 11 · 5 and 16 · 5 are considered for the current simulations. Laminar flow to turbulent flow regimes over the ducts are briefly presented and discussed. Results show enhancement in heat transfer through the CW-CCW, hexagonal and straight square ducts(SSD) for the laminar as well as for turbulent regimes are figured out and perfectly described. It is seen that in laminar regime, twisted CW-CCW square duct performed well than twisted square and hexagonal duct. A comparison of friction coefficients are also established for both the channels. Less friction factor is observed for twisted CW-CCW duct compared to other duct.