FLOW VISUALIZATION OF CONVEX LOUVER FIN ARRAYS TO DETERMINE MAXIMUM HEAT-TRANSFER CONDITIONS

A flow visualization study was performed for the convex louver fin geo metry. The visualization was achieved using dye in a 20:1 scale model with water as the fluid. The louver angle and fin pitch were varied to determine the conditions that produced maximum mixing and therefore a re expected to produce maximum heat transfer. The mixing efficiency wa s described using a dye mixing angle. The Reynolds number based on lou ver length was varied from 400 to 3000. For most configurations, the m ixing angle increased with Reynolds number. Louver angles of 19 and 24 -degrees were tested. For each value of fin pitch (F(p)) to chevron he ight (H), the larger louver angle resulted in a large mixing angle. F( p)/4H = 1, 1.5, 2 and 3 were tested the F(p)/4H = 1.5, producing the l argest mixing angle. The separation structure produced by the convex l ouver geometry was also studied using flow visualization.