A new method of CFD simulation of airflow characteristics of swirling floor diffusers

Air supply diffusers used in air-conditioning systems can be classified as ceiling diffusers, sidewall diffusers, floor diffusers, jet nozzles, and low velocity displacement diffusers. Fixed or adjustable slats are usually used to control airflow directions.
Recently, swirling vanes are used in floor diffusers to create swirling outflow jet, so that more rapid mixing with ambient air can be achieved. In this paper we used the latest CFD technique to investigate the airflow pattern and the impact on thermal comfort in the near nozzle region of a floorlevel swirl-type diffuser. The preliminary simulation results indicate that re-circulation region in the near nozzle can only be realistically predicted by including the swirling devices in the calculation domain. The results will be further validated with experiments, and the method is expected to be used to help optimize diffuser designs.