Effect of personalized air curtain combined with mixing ventilation on dispersion of aerosols released at different velocities from respiratory activities during close contact

Abstract

Release velocities of aerosols vary among people and respiratory activities. To better promote the application of personalized air curtain (PAC) in practice, this work investigated the performance of PAC combined with mixing ventilation in terms of dispersion of aerosols released at different velocities using a simulation approach of computational fluid dynamics (CFD). The healthy person (HP) and infected person (IP) were in face-to-face and face-to-back scenarios during close contact. Results showed that the aerosol dispersion was highly affected by aerosol release velocities. When aerosols were released from 2.0 m/s to 8.0 m/s, the deposition rate was increased by more than 3 times and 10 times in the face-to-face and face-to-back scenarios, respectively. The intake fraction was increased by over 3 times in the face-to-face scenario. PAC could significantly reduce the intake fraction and deposition rate. When aerosols were released at 8.0 m/s, PAC could reduce the intake fraction and deposition rate by 76% and 66% in the face-to-face scenario, respectively. A higher PAC velocity did not necessarily lead to a better performance. The appropriate PAC velocity of 3.0–5.0 m/s was suggested in this work. The significantly reduced intake fraction and deposition rate suggest that PAC as an advanced ventilation system can be a promising control measure to prevent the spread of respiratory diseases in indoor environments. Additionally, different performances of PAC indicate the importance of investigating the appropriate PAC velocities in relation to aerosol release velocities. Otherwise, more energy is consumed by PAC, but the best performance is not achieved.