Fluid Flow and Heat Transfer of Opposing Mixed Convection Adjacent to Downward-Facing, Inclined Heated Plates

Experimental investigations were carried out for opposing mixed convective flows of air adjacent to downward-facing, inclined heated plates. The experiments covered the ranges of the Reynolds and modified Rayleigh numbers from Re-L = 400 to 4600 and Ra-L* = 1.0 x 10(7) to 5.4 x 10(8), and the inclination angles from theta = 15 to 75 degrees from horizontal. The flow fields over the plates were visualized with smoke. The results showed that a separation of forced boundary layer flow occurs first at the bottom edge of the plate, and then the separation point shifts toward upstream with increasing wall heat flux, and finally, reaches the top edge of the plates. It was found that the separations at the bottom and top edges are predicted with a non-dimensional parameter (Gr(L theta)*/Re-L(2.5)) = 0.35 and 1.0, respectively. The local heat transfer coefficients of the inclined plates were also measured and the results showed that the minimum coefficients appear in the separation region. Moreover, it was revealed that forced, natural, and combined convective flows can be classified by the non-dimensional parameter (Gr(L theta)*/Re-L(2.5)). (C) 2008 Wiley Periodicals, Inc.