Abstract
Direct numerical simulation of laminar flow in model heat exchangers with oblique wavy walls is made in order to assess the heat transfer and pressure loss characteristics for the optimal shape design of recuperators. The effect of oblique angles of the wavy walls is systematically evaluated. It is revealed that the flow structures are drastically modified due to the strong secondary flow induced by the wavy walls, and that the heat transfer enhancement could be greater than the pressure loss penalty with optimal surface geometries and flow configuration. It is also found that the averaged Nu number is increased when thermal coupling of hot and cold fluid passages is considered.
