Numerical Analysis of Fluid Flow and Heat Transfer in Entrance and Fully Developed Regions of a Channel With Porous Baffles

Abstract

In the present study, analysis of fluid flow and heat transfer in the entrance and periodically fully developed regions of a channel with porous baffles is numerically studied. The Navier–Stokes and Brinkman–Forchheimer equations are used to model the fluid flow in the open and porous regions. The flow is assumed to be laminar. A finitevolume based method in conjunction with the SIMPLE algorithm is used to solve the equations. The local thermal equilibrium model is adopted in the energy equation to evaluate the solid and fluid temperatures. The effects of parameters such as baffle height, baffle spacing, Reynolds number, and thermal conductivity ratio between the porous baffles and the fluid on the flow field and local heat transfer rate are studied at relatively low and high values of Darcy number. Results show that local heat transfer coefficient significantly depends on the formation and variation of the recirculation caused by the porous baffles, such that, in the cases where use of porous baffles leads to recirculation zone, the local Nusselt number in the entrance region would be less than that of the fully developed region. It is also shown that heat transfer performance ratio is significantly improved for high Prandtl number fluids.