Numerical Modeling of Free-Convection in Sinuous Channels with Leveled and Unleveled Ports

Abstract

In this article, we numerically study natural convection in U-shaped channels oriented upward or downward. The figure of merit considered is the global conductance. Several opportunities for shape optimization have been revealed. In particular, the following features of U-shaped channels have been varied: spacing between the two vertical channels, breadths of the vertical channels, curvature radii of the connection between the two vertical channels, and the inlet-to-outlet height difference. We also studied the impact of nonuniform heat inputs in the channels and the effect of sequencing two interconnected U-shaped channels. Results suggest that upward facing U-shaped channels offer higher global conductance than their downward facing counterpart. Additionally, the results indicate that the curvature radii of the internal and external surfaces of the U-bend have a minor effect on the figure of merit if the bent breadth does not constrict the flow. Finally, the results show that significant improvements in terms of thermal performance are obtained if non-uniform heat flux conditions are imposed to the heated wall.