Effect of Boundary Wall Conditions on Heat Transfer for Fully Opened Tilted Cavity

An experimental investigation was performed to study the effect of wall conditions as well as the tilt angle on heat transfer for fully opened tilted cavity. The cavity has a rectangular shape with a square cross section. One side is fully opened to the ambient, permitting air to flow inside the cavity by virtue of buoyancy. The cavity was selected to be long enough to simulate two-dimensional natural convection. Seven cases with different wall configurations were examined: (a) three of which with only one wall heated and the other two were insulated, (b) three of which with two walls heated and the other one was insulated, and (c) a case with all walls were heated. The heated walls were maintained at constant heat flux, which correspond to a constant Grashof number of $1.3×108.$ In each case, the cavity was rotated over a range of ±90 deg (measured from the vertical direction) in 15 deg increments. It was concluded that tilt angle, wall configuration, and the number of heated walls are all factors that strongly affect the convective heat transfer coefficient between the cavity and the ambient air. Empirical correlations were provided to predict the average Nusselt number at different inclination angles for all seven cases. It was found that the correlations could predict the result to within 4 to 10 percent, depending on the inclination angle and the case considered.