EXPERIMENTAL-STUDY OF LAMINAR NATURAL-CONVECTION IN CELLS WITH VARIOUS CONVEX AND CONCAVE BOTTOMS

Heat transfer and free convective motion in limited space from the bottoms of different hemispherical convex or concave shapes have been studied experimentally. The ratio of the diameter of the hemisphere (d) to the diameter of the bottom (D) (0 < d/D < 1) has been tested for a range of Rayleigh numbers (10(5) < Ra < 10(7)). In comparison with a flat bottom (d/D = 0), about 40 percent inhibition or about 50 percent intensification depending on the bottom configuration (d/D) have been observed. The mechanism of the phenomenon based on dead space, local overheating, and shape influence effects has been proposed.