Thermal Interaction and Chimney Effects on Natural Convective Cooling Performance of Heat Generating Blocks Mounted on a Board in a Two-Dimensional Cabinet

Abstract

This study aims to investigate numerically the effect of thermal interaction between the air streams inside and outside a cabinet on the cooling performance of heat generating blocks mounted on a board in the two-dimensional square cabinet. Moreover, air vents are proposed to construct in the cabinet wall; the thermal buoyant force can induce air to flow through the cabinet. Great efforts are performed to rigorously investigate the chimney effect of air vents on heat transfer enhancement of heat generating blocks in the cabinet. The computation domain covers the cabinet and the surrounding area, and the temperature and velocity fields of the cabinet and surrounding area are solved simultaneously. Results show that the thermal interaction and air vents can significantly affect the cooling performance of heat generating blocks. The maximum difference in hot spot temperatures of the blocks for the situations with and without consideration of thermal interaction can be up to 44%, as Pr = 0.7, 10⁴ ≦ Ra ≦ 10⁶ and 10 ≦ K _bf  = K _pf  = K _wf  ≦ 100. When three vents are constructed in the cabinet wall, the hot spot temperature can be reduced by 45%. On the other hand, the difference in the hot spot temperatures for cases with two and three air vents is within 6%.

The financial support of this study by the Engineering Division of National Science Council, R.O.C. through contract NSC-96–2221-E-150–040 is greatly appreciated.