Characterizing exhaled airflow from breathing and talking

Abstract

Practical ImplicationsAccurate prediction of airborne disease transmission, and the infection prone zones, can aid in identifying and implementing the control strategies. With the recent advancements, Computational Fluid Dynamics (CFD) has become a powerful tool in predicting the disease transmission. Accurate prediction of the transmission by these CFD simulations requires information on sources and sinks of infectious viruses and models for dispersion of these viruses. The exhaled air of an infected human is one of the prime sources of disease viruses. In the present study, measurements of the flow were conducted on human subjects to develop models for the flow boundary conditions for the exhalation and inhalation during breathing and talking.

Characterizing the Dynamic Interactions and Exposure Implications of a Particle-Laden Cough Jet with Different Room Airflow Regimes Produced by Low and High Momentum Jets

“…A more detailed overview on the structure of the cough generator can be found in our latest study (Liu and Novoselac, 2014). The cough generator produces a square-wave manner cough that is different from cough's released from the human body and in previous studies (Zhu et al, 2006;Gupta et al, 2009). During measurement period, a stable particle concentration in the cough jet was achieved.…”

“…The airtemperature was kept as 32.0 ± 0.5°C inside the cough generator by using a 12-voltage 20-watt tungsten halogen bulb. The total cough volume may have a variation of 0.8-5.0 L cough -1 (Zhu et al, 2006; Gupta et al, 2009). In this study, the total cough air volume was set as 1.4 L cough -1 with a maximum cough velocity of 6.0 m s -1 over a period of 1 second.…”

“…The temperature of a cough with smoke was kept as 32.0 ± 0.5°C in the cough generator. Earlier studies show that droplet dispersion may extend to 0.6-0.9 m from mouth (Jennison, 1942;Edgerton and Barstow, 1995;Gupta et al, 2009). The smoke visualization of the interaction between a cough jet, ventilation discharge jet and thermal plumes were made for two distances between two dummies, 0.5 m and 0.8 m.…”

“…Chao et al (2008) found that the lateral dispersion behaviour was dominated by the ventilation airflow and the effect of the thermal plume was relatively minor for the 1.5-45 µm droplets with lower supply airflow rate. It is well known that a cough may be one of the prime infectious sources of airborne diseases as it has a high velocity and large quantity of droplets (Gupta et al, 2009(Gupta et al, , 2011. A number of studies have investigated the basic characteristics of a human's cough regarding velocity distribution and size distribution of droplets.…”

A MEMS turbine prototype for respiration harvesting

“…In addition to these body activities, normal respiration also poses great potential for energy harvesting. Detailed studies on human breathing showed that watt-level power is available in the form of fluid flow [8][9][10], which indicates that milliwatts can be generated with a harvester having a few percent efficiency.…”