Performance analysis of a novel personalized air curtain for preventing inhalation of particulate matters in industrial environments

Abstract

Personalized air curtains promise to reduce respiratory exposure in industrial environments. This work explored the performance of normal safe helmets equipped with air curtains to prevent workers from particulate matters via computational fluid dynamics (CFD) method. The impact of human body heat, breathing modes (nose and mouth inhalation), and air curtain characters (opening angle, tilt angle, and opening width) on protective efficiency were analyzed under different air supply velocities. Results showed that the interaction between the downward jet supplied by the air curtain helmet and the free convection flow generated by the thermal human body significantly affects respiratory exposure. There is a critical air supply velocity, i.e., when the jet velocity is greater than this value, the flow field in the breathing zone was dominated by the downward jet; otherwise, it is dominated by free convection flow. Both human body heat and breathing modes have significant effects on the protective effect of the air curtain. The opening angle of 180o, the tilt angle of 0o, the opening width of 3 cm, and the air supply velocity of 0.5 m/s are recommended due to a high protection effect of around 1. This study can provide effective and intuitive guidance in applying personalized air curtains for respiratory protection in highly contaminated industrial environments.