Transport and trajectory of cough-induced bimodal aerosol in an air-conditioned space

Abstract

Aerosol generated from a human cough can be a potential major indoor health risk due to the possible transmission of infectious respiratory diseases to surrounding individuals within the same room and even could spread out via air-ventilation/conditioning systems. This study aims to investigate the transport characteristics and trajectory of coughed aerosols under the influence of conditioned air ventilation as well as near-by human breathing zone using computational fluid dynamics (CFD). An experimental system consisting of air-conditioned space with multiple inlets and outlets, a cough simulator and a receiver was built to validate the CFD predictions. The comparison is in good agreement. The CFD model was established as a transient three-dimensional multiphase multicomponent Eulerian–Lagrangian model and numerically solved using commercial software ANSYS Fluent. Both gas and liquid phases were modelled as multicomponent mixtures. With this CFD model, the indoor transport and trajectory of coughed aerosols can be accounted for the distributions of portions inhaled by each manikin, deposited on surfaces of manikins and chamber walls, as well as recirculated back into the ventilation system. Results reveal that the aerosol source location and the ambient air movement can be crucial factors of aerosol trajectory in terms of direct and indirect influence.

Evaluation of indoor disinfection technologies for airborne disease control in hospital

“…23 Computational fluid dynamics (CFD) has been proven to be effective and reliable to simulate the indoor air flow field and respiratory droplets trajectory. 24 However, the limitation of CFD engineering application are computing time and cost. For a room with complex geometries, CFD may take several hours even several days to finish optimization processes.…”

Propagation of Mouth-Generated Aerosols in a Modularly Constructed Hospital Room

“…The simulations were performed on SHARCNET, which provides supercomputers that are efficient in performing different numerical simulations. The adopted numerical characteristics followed the study by Zhang et al [12]. To numerically model the injection of saliva particles, a Lagrangian model was used to model the flow of liquid droplets within the air flowfield, which lasted for 1.0 s (i.e., cough duration).…”

“…To validate the numerical models used to simulate the propagation of mouth-generated aerosol in a modular room, a study conducted by Zhang et al [12] involving a comprehensive comparison between a full-scale experimental system and CFD simulation of an air-conditioned chamber, was used to assess the transport and the trajectory of coughinduced aerosol. The chamber geometry is 2.9 m long, 2.3 m wide and 2.0 m high, which includes four manikins sitting on chairs to simulate a gathering, as shown in Figure 2.…”

“…The rate at which the volume of air being exchanged which is known as air changes per hour (ACH) can impact the final position of aerosols in the ward [12]. In general, the health care system can be branched into three different components: (i) equipment, (ii) personnel, and (iii) space.…”

Airborne Transmission of Virus-Laden Aerosols inside a Music Classroom: Effects of Portable Purifiers and Aerosol Injection Rates

“…Numerical modeling (computational fluid dynamics, CFD) have been used to good effect in modeling the spread and transport of droplets via sneezing, coughing and other expiratory events 12–18 . There have been several numerical studies simulating the spread and deposition of viral droplets and aerosols in both outdoor environments 19,20 and enclosed spaces such as hospital wards, office spaces, aircraft cabins and urinals through CFD simulations 5,18,21–31 .…”