Fluid Flow and Heat Transfer of Mixed Convection Adjacent to Vertical Heated Plates Placed in Uniform Horizontal Flow of Air

Experiments have been carried out for mixed convective flows of air adjacent to the vertical heated plates in uniform horizontal forced flows to investigate relationships between the flow and the heat transfer. The experiments cover the ranges of the Reynolds and modified Rayleigh numbers: Re-L = 160 to 2300 and Ra-L* = 4.3 x 10(5) to 2.0 x 10(8). The flow fields over the plates are visualized with particles and smoke. The results show that a stagnation point moves downward away from the center of the plate when the surface heat flux is beyond a critical value. The condition where the stagnation point begins to move is expressed with non-dimensional parameters as: Gr(L)*/Re-L(2.5) = 0.15. Profiles of measured local heat transfer coefficients are smooth even at the stagnation points in all the cases examined. When buoyancy effect is sufficiently weak, the coefficients agree well with those of the wedge flow. With increasing the surface heat flux, the coefficients are augmented to approach asymptotically the boundary layer solution of natural convection along a vertical heated plate. Finally, forced, mixed, and natural convection regimes are classified by the non-dimensional parameter (Gr(L)*/Re-L(2.5)). (C) 2009 Wiley Periodicals, Inc.