If the swirling airflow is formed in the room, the ventilation effectiveness in the room becomes better than by the other method, as the airflow pattern has the fixed direction and the stable airflow path is built up. To make swirl the room air, it is necessary to supply getting larger airflow rate toward outer zone from center. To supply such an airflow distribution simply is used the multi-openings square duct. The reason is that the supply airflow distribution of multi-openings duct has a tendency to increase toward the tip. The analysis is conducted by the k-e two-equations turbulence model. The airflow simulation in space is conducted and examined about whether the swirling is formed or not. From the view of the ventilation effectiveness, the results are comparison with the ceiling cassette type air-conditioning system and the duct type with uniform supply airflow distribution. The assumption space are a gymnasium and a supermarket, they are examined about the distribution of airflow, contaminant diffusion and ventilation effectiveness.
Ventilation effectiveness of large space with swirling airflow formed by the multi-openings square ducts.
Hong Kong, City University, Division of Building Science and Technology, 2001, proceedings of IAQVEC 2001, "Indoor Air Quality, Ventilation and Energy Conservation in Buildings: Fourth International Conference", held Changsha, Hunan, China, 2-5 October, 2