A numerical model of convective heat transfer in a three dimensional channel with baffles

Abstract

A numerical investigation of laminar forced convective heat transfer was performed in a three-dimensional channel with baffles in which a uniform heat flux was applied to the top and bottom walls, and the side walls were considered adiabatic. The trade-off between heat transfer enhancement and pressure drop produced by the baffles was studied for periodically fully developed flow (PDF). The numerical analysis was performed using a finite volume approach. The computer code was validated against the experimental results of Goldstein and Kreid (1967) and Beavers et. al. (1970) for a three-dimensional laminar flow in a channel without baffles. Parametric runs were made for Reynolds Numbers (Re) of 150, 250, 3 50, and 450, for blockage ratios (H/Dy) of 0. 5, 0.6, 0. 7, 0.8. Heat transfer behavior was studied for Prandtl Numbers (Pr) of 0. 7 and 7. 0, and for wall thermal conductivity to fluid thermal conductivity ratios (K) of 1, 10, 100 and 1000. It was found that three dimensional effects were present for the range of Reynolds number studied. The pressure drop penalty becomes highly important above blockage ratios of 0.7. Higher heat transfer enhancement was found for high Prandtl numbers (Pr--7. 0) than for low Prandtl numbers (Pr--O. 7). The heat transfer enhancement due to an increase in the thermal conductivity ratio of the solid to the fluid regions is greater than the one obtained by increasing the blockage ratio.