NATURAL-CONVECTIVE HEAT TRANSFER IN A SQUARE CAVITY WITH TIME-VARYING SIDE-WALL TEMPERATURE

ABSTRACT

The natural-convective heat transfer in an inclined square enclosure is studied numerically. The top and bottom horizontal walls are adiabatic, and the right side wall is maintained at a constant temperature T ₀. The temperature of the opposing vertical wall varies by sine law with time about a mean value T ₀. The system of Navier–Stokes Equations in Boussinesq approximation is solved numerically by the control-volume method with SIMPLER algorithm. The enclosure is filled with air (Pr = 1) and results are obtained in the range of inclination angle 0° ≤ α ≤ 90° for two values of Grashof number (2 × 10⁵ and 3 × 10⁵). It can be noted that there is a nonzero time-averaged heat flux through the enclosure at α ≠ 0°. The dependencies of time-averaged heat flux on oscillation frequency and inclination angle are depicted. It is found that the maximal heat transfer corresponds to the values of inclination angle α = 54^○ and dimensionless frequency f = 20π for both Grashof numbers studied (2 × 10⁵ and 3 × 10⁵).

A preliminary version of this article was presented at CHT-04: An ICHMT International Symposium on Advances in Computational Heat Transfer, April 2004, G. de Vahl Davis and E. Leonardi (eds.), CD-ROM Proceedings, ISBN 1-5670-174-2, Begell House, New York, 2004.