Air Flow Thermal and Dynamic Behavior Inside Ventilated Cavities

Abstract

This work presents a numerical study of the dynamic and thermal behavior of the air flow circulating in the vertical rectangular cavity of height H and width W. The geometry consists of a vertical wall of low thermal conductivity and an opposite wall which acts as a ventilated facade with five openings subjected to a heat flow. The methods of analyzing the flow input and output behavior through the openings throughout the ventilated facade, make the use of CFD tools "Fluent 14.0" mandatory for a detailed description. The flow is considered to be turbulent, steady, incompressible and bi-dimensional and computations are performed using the standard k-ε and RNG k-ε models for Rayleigh number ≈ 10¹¹. The results included mean velocity profiles; flow structure and thermal field which were presented and discussed. A comparative study with conventional cavity (closed) and classical cavity with two openings (input-output) under the same thermal conditions was conducted to quantify energy savings by the use of such configuration. The increase of the number of the openings enhances the wall cooling. Moreover, above a certain heat flux absorbed by the ventilated wall, natural cooling is obsolete, it is necessary to use forced devices.