Design and characterization of a cough simulator. (23rd February 2017)

• Record Type: Journal Article
• Authors: Zhang, Bo; Zhu, Chao; Ji, Zhiming; Lin, Chao-Hsin
• Is Part Of: Journal of breath research. Volume 11:Number 1(2017:Mar.)
• Publication Date: 2017-02-23
• Subjects: cough -- experiment -- CFD -- parametric model -- disease -- size distribution; Volatile organic compounds -- Analysis -- Periodicals; Clinical chemistry -- Periodicals; Bad breath -- Periodicals; Bad breath -- Treatment -- Periodicals; Bad breath -- Diagnosis -- Periodicals; 616.0756
• DOI: 10.1088/1752-7163/aa5cc6
• Languages: English
• ISSNs: 1752-7155

Abstract

Abstract: Expiratory droplets from human coughing have always been considered as potential carriers of pathogens, responsible for respiratory infectious disease transmission. To study the transmission of disease by human coughing, a transient repeatable cough simulator has been designed and built. Cough droplets are generated by different mechanisms, such as the breaking of mucus, condensation and high-speed atomization from different depths of the respiratory tract. These mechanisms in coughing produce droplets of different sizes, represented by a bimodal distribution of 'fine' and 'coarse' droplets. A cough simulator is hence designed to generate transient sprays with such bimodal characteristics. It consists of a pressurized gas tank, a nebulizer and an ejector, connected in series, which are controlled by computerized solenoid valves. The bimodal droplet size distribution is characterized for the coarse droplets and fine droplets, by fibrous collection and laser diffraction, respectively. The measured size distributions of coarse and fine droplets are reasonably represented by the Rosin–Rammler and log-normal distributions in probability density function, which leads to a bimodal distribution. To assess the hydrodynamic consequences of coughing including droplet vaporization and polydispersion, a Lagrangian model of droplet trajectories is established, with its ambient flow field predetermined from a computational fluid dynamics simulation.