Analysis of a Natural Convection/Thermosyphon Mechanism for Heat Rejection from Enclosures

摘要

The problem of electronic component cooling in rectangular tall vertical enclosures heated at the bottom, and cooled from the sides and top is investigated numerically. The investigation considers both 2-D and 3-D enclosures, with emphasis on the 2-D configuration. Several performance parameters are considered. The maximum power that can be dissipated from these enclosures is found for varying aspect ratios, with consideration given to radiation effects, finning, and heater geometry. Limiting criteria are that the air temperature below the heated elements be 343 K with a 298 K ambient. Heat rejection for all configurations was almost linear with aspect ratio (enclosure area). The plane wall with radiation exhibited significantly better cooling at higher aspect ratios while the optimally finned wall exhibited improved cooling at lower aspect ratios. The effects of radiation and finning are nearly additive when combined. The results comparing the 2-D and 3-D plane wall enclosures showed very close agreement and heater element configuration was shown to have small effects on cooling performance.