Numerical study on heat transfer enhancement in a rectangular duct with incline shaped baffles

Abstract

This research is aimed to study on heat transfer enhancement in a heat exchanger by installing inclined shape baffles to create co-rotating vortex flow using the Computational Fluid Dynamics (CFD) method with the k-e and RNG models. According to the FLUENT program, air is used as the test fluid which consists of the rectangular duct with a height (H) of 30 mm, and the Reynolds number (Re) in a range of 12,000 to 35,000. It is important to study the Nusselt number, Nu and the friction factor, f in order to earn the result from their relation analysed for the Thermal performance Enhancement Factor (TEF). As a results, the experiment of CFD showed a smooth duct and shaped baffles duct (with baffle- to channel-height ratios (e/H) at 0.1, 0.2 and 0.3 and the angle of attack (α) 30°, 45° and 60°) comparing with another research (Benjapol; et al. 2014). It is found that Nu and f are related in a range of -10% to +10%. While the velocity vector and temperature contours indicated that the increasing of α and the baffles height can increase co-rotating vortex flow in spite of decreasing TEF. The optimum α is 45° with e/H 0.3 which represents the highest TEF at 1.74. © Copyright 2017, AIDIC Servizi S.r.l.