Numerical and Experimental Investigations of Heat Transfer Enhancement in a Duct Heater with Different Areas of Vortex Generators

Abstract

Numerical and experimental investigations were carried out on the effect of the vortex generators on the flow field and heat transfer from duct heaters. The flow Reynolds number ranging from 32000<Re<83000 with a constant heat flux of 43.09426.

In the numerical investigation, Fluent package (6.3) was used to solve the steady, (3-D), continuity, momentum and energy equations where the standard (k-?) model was used to remedy the turbulent effects. Theoretical results show that the presence of VGs would save 27% of heaters power. The effects of two areas of VGs were looked at a small circle cross section vortex generator (SCCSVG) and a big circle cross section vortex generator (BCCSVG) of similar shapes (where).

The experimental results showed that there were an enhancement in heat transfer with the presence of VGs and heat transfer depends on VGs’ areas. The BCCSVG was the better one of enhancing heat transfer by (2.76%-4.11%). Additionally, the increase of area of VGs, number of rows for VGs and the distance between each two rows of VGs and the heaters are the most effective parameters in improving the performance of heat transfer.