Heat Transfer Enhancement for Internal Flows with a Centrally Located Circular Obstruction and the Impact of Buoyancy

Abstract

Numerical simulations have been carried out for gas flow through a horizontal pipe. Accounting is made of buoyancy effects, changes to the thermophysical properties, and the presence of a blockage. It was found that for low-to-moderate Reynolds numbers, the combined effects on heat transfer and pressure loss lead to an improved performance with the obstruction. On the other hand, the influence of heating on properties is shown to have a significant effect on the Nusselt number in both the laminar and the turbulent regions. Property variations increase the laminar Nusselt number and decrease the turbulent values. The results also show that a blockage has a much bigger impact on laminar flows than on turbulent flows and can inhibit downstream buoyant motion and convective heat transfer.