THREE-DIMENSIONAL NATURAL CONVECTION IN A CORRUGATED ENCLOSURE

摘要

Numerical solutions for the problem of three-dimensional natural convection in an enclosure with a corrugated surface are presented in this work. The enclosure is formed by five flat surfaces and a corrugated section. The corrugated and top surfaces, are respectively heated and cooled isothermally. The side flat surfaces are maintained at adiabatic conditions. The working fluid in the enclosure is air (Pr=0.71). The effects of geometric parameters such as enclosure aspect ratio, amplitude aspect ratio, inclination angle, and number of corrugation cycles are presented.The solution scheme employs an algebraic transformation of the enclosure geometry which maps the physical domain into a rectangular domain to avoid the task of numerically generating boundary-fitted coordinates. The resulting transformed governing equations and boundary conditions are solved within the framework of the SIMPLEST scheme.Results are obtained for Rayleigh numbers ranging from 0 through 5×10~5 and orientation angles of 30 and 60 degrees. The enclosure aspect ratio is set at 5, with two cycles of corrugation. The corrugation amplitude aspect ratio is fixed at 0.4. Results show that the average effective heat transfer in the cavity increases with increasing Rayleigh number, and under isothermal conditions with no external convection, an increase in the orientation angle produces an increase in the average effective heat transfer in the enclosure.