Fluid Flow and Heat Transfer of Opposing Combined Convection Adjacent to Vertical Heated Plate (Water Case)

Abstract

Experimental investigations have been carried out on fluid flow and heat transfer of opposing combined forced and natural convection of water adjacent to a heated vertical plate. The length of the plate, L, are L = 50, 100 and 150 mm. The plate is heated with a constant heat flux. The experiments cover the range of Reynolds and Rayleigh numbers as; 4×10² < Re_L < 5×10³, 4×10⁶ < Ra_L* < 3×10¹¹．The flow fields around the plate were visualized with dye. The result shows that the separation of the laminar boundary layer of forced convection appears first at the bottom edge of the plate when the non-dimensional parameter (Gr_L^*/Re_L^2.5) = 0.4 and the separation point reaches to the reading edge when (Gr_L^*/Re_L^2.5) = 3. The local heat transfer coefficients from the plates were subsequently measured with thermocouples. The result shows that the coefficients deviate from those of the pure-forced convection with the onset of flow separation at the bottom. It is also found that the combined convection region was determined as; 0.35 < (Gr_L^*/Re_L^2.5) < 4.0.