Improvement of CFD application in ventilated enclosures: a test case.

The aim of this study is to improve the utilization of CFD approach in the applications of air conditioning technology. More precisely, to establish principles and recommendations to follow in order to design air distribution systems in small enclosures at low room air changes per hour by means of CFD technique. By the use of a commercial code, Fluent, the accuracy and reliability of such a numerical simulation are elucidated in this work for a mixing ventilation system; the air supply terminal is a commercial diffuser which creates a complicated 3D - wall jet below the ceiling. We focus on the factors which have a major impact on the simulations: the description of the computational domain (particular emphasis is put on the supply airflow conditions), the turbulence model and the near wall treatment. Comparisons between predicted and measured values are given in terms of mean air velocity and temperature. The validation of the simulations is completed by an analysis related to analytical expressions for the velocity profile and centerline velocity decay of a three dimensional jet.