Particle dispersion during speaking in a ventilated hospital visiting room

The epidemic of corona disease in recent years has led to significant loss of life and economic and social disruptions all over the world. Hospital environments are places with high risk of disease transmission and the risk of transmission of infectious diseases to hospital staff is very high. The main cause of transmission of infectious respiratory diseases are viruses that are surrounded by mucus and saliva droplets that are spread to the environment through respiratory activities such as sneezing, coughing, breathing and speaking. As soon as the droplets enter the environment, evaporation begins due to the difference in relative humidity inside the body and the outside in environment. Depending on the mass of the droplets, the drop may settle in the environment or accompany the prevailing air flow. When the water or mucus of a droplet completely evaporates, the droplet core containing all the viruses in the original droplet remains in the air for a long time in the environment. Many factors affect the dispersion of particles. The ventilation system, how injection occur (angle, velocity and...), the relative humidity of the room, etc. are factors affecting the dispersion of particles. In the present work, the effect of the position of the patient and the doctor on the scattering of particles in a hospital visiting room has been studied. A hospital visiting room is modeled with two patient and doctor manikin. It was assumed that one of them was speaking and emitting small droplets. Then, the effect of two position of sitting doctor and sitting patient oposit side (DSPS) and standing doctor and lie downing patient (DSPL) on the transmission and dispersion of droplets was simulated. These simulations were performed using Computational Fluid Dynamics (CFD) approach with Ansys-Fluent software. The Euler approach was used to simulate the air flow field in the room and the Lagrangian path analysis approach was used for the droplets. The experimental data of the thermal column above the head of the mannequin was used to confirm the results of air flow simulation. The results showed that the particles settle down more in the lying state than in the sitting state, and a smaller percentage of the particles remain airborne in the space.

کلیدواژه ها:

CFD simulation ، hospital visiting room ، particles ، talking ، infectious disease