Numerical investigation of conjugate heat transfer and flow performance of a fin and tube heat exchanger with vortex generators

Abstract

Vortex generator is considered as an effective device for augmentation of the thermal-hydraulic performance of a heat exchanger. The aim of present study is to examine the influence of vortex generators on a double fin and tube heat exchanger performance. Vortex generator of rectangular winglet type is chosen and investigated at different angles of attack 0 • , −10 • and −20 • with the flow direction. Three-dimensional numerical model is developed and simulations are performed for a Reynolds number range 5000 ≤ Re ≤ 11000 taking conjugate heat transfer into account. The heat transfer and pressure loss characteristics are determined and analyzed for an in-line configuration of a fin and tube heat exchanger. In order to evaluate the enhancement in the performance on an equitable basis, the heat exchanger with plain fin surface is considered as a reference design. Results show that the angle of attack of a vortex generator has a significant impact on the volume goodness factor, and enhance the thermal performance of a fin and tube heat exchanger in comparison to the design with plain fin. The vortex generator at an angle of attack −10 • is found to perform superior over the Reynolds number range studied. At Re = 5000, the vortex generator with an angle of attack −10 • increases the volume goodness factor by 32% with respect to the baseline heat exchanger design.