Numerical modeling of a sneeze, a cough and a continuum speech inside a hospital lift

Chillón, Sergio A.; Fernandez-Gamiz, Unai; Zulueta, Ekaitz; Ugarte-Anero, Ainara; Urbina-Garcia, Oskar

doi:10.1016/j.heliyon.2023.e13370

Cited by 6 publications

(3 citation statements)

References 43 publications

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“…[23][24][25] Many scholars have used computational fluid dynamics (CFD) simulation methods to study the movement and distribution rules of bioaerosol indoors and obtained some important conclusions. [26][27][28][29][30] A study by Dao et al 31 predicted the effect of air outlet location and particle water content on the distribution characteristics of bioaerosols. The results showed that the best ventilation was achieved with a scheme that arranged the air outlet above the infector's head.…”

Section: Introductionmentioning

confidence: 99%

Spatial and temporal distribution of bioaerosols produced by patients with different postures in a negative pressure isolation ward under different ventilation modes

Li,

Ma,

Liao

2024

Indoor and Built Environment

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The high concentration of viral bioaerosols within the negative pressure isolation wards could pose a challenge to preventing potential cross-infection amongst healthcare workers (HCWs) and patients. Using the Euler–Lagrange methodology, this study numerically simulated the spatial and temporal distribution characteristics of bioaerosols in a typical negative pressure isolation ward as well as determined the interaction of ventilation mode and patient posture on ward ventilation performance. The removal effect of particle groups produced by two respiratory behaviours (breathing and coughing) was quantitatively analyzed, and the effect of exhaust air ratio and air exchange rate on particle distribution was discussed. The results showed that the migration characteristics of bioaerosol particles were sensitive to both the ventilation pattern and patient posture, which showed significant interactions. On this basis, the ventilation pattern with the best ventilation performance was evaluated, showing a particle removal effect of 70–85%. Due to the initial momentum difference, the diffusion behaviour of cough and breath particles was not consistent, but optimizing the airflow distribution near the exhaust outlet could improve their removal efficiency in the meantime. Further studies found that equal exhaust air velocity ratio facilitated the removal of aerosol particles, and an appropriate increase in the air exchange rate could also reduce the particle content.

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Section: Introductionmentioning

confidence: 99%

Spatial and temporal distribution of bioaerosols produced by patients with different postures in a negative pressure isolation ward under different ventilation modes

Li,

Ma,

Liao

2024

Indoor and Built Environment

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“…The recognition of transmission modes has led to extensive research efforts aimed at addressing these crucial issues. [9][10][11] However, recent scientific studies indicate that COVID-19 could also be transmitted through smaller particles known as aerosols, which have a diameter of less than 5 μm. 12 Respiratory droplets, as well as aerosols, have the capacity to remain suspended in the air for a defined duration and can be transported by airflows, enabling them to traverse particular distances.…”

Section: Introductionmentioning

confidence: 99%

Numerical modelling of ventilation strategies for mitigating cough particles transmission and infection risk in hospital isolation rooms

Korany,

Almhafdy,

AlSaleem

et al. 2024

Indoor and Built Environment

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This study used numerical modelling to analyze air velocity, cough particle distribution and infection risks in an isolation room. It investigated air change rates, inlet/outlet vent positioning and assessed various ventilation rates and outlet configurations for reducing infection risks. Quantitative assessments revealed different particle escape timings. In Case 1, smaller particles (2–4 μm) took 8.2 s to escape, while in Case 2, this time extended to 22.7 s. At 48 ACH, there were significant improvements in removing particles of various sizes, particularly those sized 2–4 μm, 16–24 μm and 40–50 μm, reducing the infection risk. The use of the Wells-Riley model highlighted considerable reductions in infection probabilities with higher ACH. Specifically, infection risks were reduced to 5% in Case 1 and 17% in Case 2, underscoring the marked advantage of Case 1 in reducing infection probabilities, particularly for smaller particles. Furthermore, escalated ACH values consistently correlated with decreased infection probabilities across all particle sizes, highlighting the pivotal role of ventilation rates in mitigating infection risks. The study comprehensively investigated the distribution of air velocity, dynamics of cough particles and infection risk associated with different ventilation strategies in isolation rooms.

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“…According to a study, in order to prevent the transmission of airborne infections, high ventilation rate requirements might be altered in both new and existing hospital designs. Chillon et al [4] used computational fluid dynamics (CFD) modeling to simulate a high-risk scenario, such as a lift in a hospital. A rack for air renewal and an extraction fan were provided for the barrier.…”

Section: Introductionmentioning

confidence: 99%

A novel transparent cabin used in the classroom during the coronavirus pandemic: a CFD analysis

ElShimi,

Morcos,

Mostafa

et al. 2024

J. Eng. Appl. Sci.

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A coronavirus family is a diverse group of many viruses. Coronavirus disease 19 (COVID-19) spreads when an infected person breathes out droplets and very small particles that contain the virus. These droplets and particles can be breathed in by other people or land on their eyes, noses, or mouths. In this paper, the airflow distribution and the movement of coronavirus particles during normal breathing and sneezing in classrooms have been studied using a CFD model developed in ANSYS® 2022R2. The objective is to find ways to control the spread of the virus that enable us to practice academic activity and deal normally with the pandemic and the spread of the disease. Experiments were done with more than one turbulence model to know which was closest to the experiments as well as to determine the best number of meshes in the classroom. The effect of turbulent dispersion on particles is resolved using a discrete random walk model for the discrete phase and the RANS model for the continuous phase in a coupled Eulerian–Lagrangian method. Furthermore, that is done in two scenarios: the first is to find the best ventilation configuration by investigating the following parameters: the effect of air change per hour, the height of the air inlets and outlets, and the infected student's position. The second is to control the spread of the coronavirus in the classroom in the event of sneezing from an infected student by placing cabins and an air filter with optimal design installed at the top around each student. It was found that optimal ventilation is achieved when fresh air enters from the side walls of the classroom at a distance of 1 m from the floor and the air exits from the ceiling in the form of two rows, and the rate change of air per hour (ACH) is 4, which leads to energy savings. In addition, a novel transparent cabin is designed for the student to sit in while in the classroom, consisting of a high-efficiency particulate air filter (HEPA) that collects any contamination and recirculates it from the top of the cabin back into the classroom with different fan speeds. Through this study, this cabin with a filter was successfully able to prevent any sneeze particles inside from reaching the rest of the students in the classroom.

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Numerical modeling of a sneeze, a cough and a continuum speech inside a hospital lift

Cited by 6 publications

References 43 publications

Spatial and temporal distribution of bioaerosols produced by patients with different postures in a negative pressure isolation ward under different ventilation modes

Spatial and temporal distribution of bioaerosols produced by patients with different postures in a negative pressure isolation ward under different ventilation modes

Numerical modelling of ventilation strategies for mitigating cough particles transmission and infection risk in hospital isolation rooms

A novel transparent cabin used in the classroom during the coronavirus pandemic: a CFD analysis

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