Critical factors to formatting and stabilizing the vortex flow in the vortex ventilation system

Vortex ventilation, which utilizes vortex airflow to effectively transport pollutants over long distances, is a promising method for pollution control in large spatial structures. The performance of vortex ventilation heavily depends on the stable generation and maintenance of column vortex airflow, necessitating a comprehensive understanding of the interactions among supply airflow, exhaust airflow, and pollutant airflow. In this study, experimental method and transient computational fluid dynamics (CFD) method were employed to quantitatively analyze the influence of supply airflow characteristics and parameters on the formation of vortex airflow. It was found that impingements between supply jet streams significantly affect the generation of vortex ventilation. Based on variations in the flow shape of supply jet streams, the process of vortex airflow formation can be divided into three stages: initiation, oscillation, and stabilization. As the airflow rate increases, the impingement effect between the air jet streams makes the vortex unstable and the vortex intensity decreases. Optimization strategies were proposed to modify system geometry, including increasing the number of supply air inlets, adjusting the horizontal deflection angle of supply air, and enlarging the size of supply air inlets. Increasing the horizontal deflection angle of supply air was shown to minimize the negative pressure within the flow field to a minimum of −12 Pa and reduce the coefficient of variation to a minimum of 0.01, which proved most effective in enhancing vortex stability.