Title: Numerical comparison of dispersion of human exhaled droplets under different ventilation methods

Authors: Zhang Lin; Jinliang Wang; Ting Yao; T.T. Chow; K.F. Fong

Addresses: Building Energy and Environmental Technology Research Unit, Division of Building Science and Technology, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong. ' Building Energy and Environmental Technology Research Unit, Division of Building Science and Technology, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong. ' Building Energy and Environmental Technology Research Unit, Division of Building Science and Technology, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong. ' Building Energy and Environmental Technology Research Unit, Division of Building Science and Technology, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong. ' Building Energy and Environmental Technology Research Unit, Division of Building Science and Technology, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong

Abstract: Stratum ventilation has been proposed to accommodate elevated room temperatures recommended by several governments in East Asia for energy saving. One key issue in evaluating the performance of stratum ventilation is whether this air distribution method performs significantly different in person to person infectious diseases transmissions. Particle dispersion in a classroom under mixing ventilation, displacement ventilation and stratum ventilation respectively are investigated by numerical simulation. The drift-flux model based on an Eulerian-Eulerian approach is adopted to simulate the particle movement in a room. The results show that the flow patterns created by different ventilation methods have great influence on the particle fates. The particle concentrations for the breathing zone under stratum ventilation are significantly lower than that under mixing ventilation and/or that under displacement ventilation, which imply that the risk of pathogen inhalation under stratum ventilation is lower than that under mixing ventilation and/or displacement ventilation.

Keywords: air distribution; stratum ventilation; airborne infections; droplet transport; droplet distribution; exhaled droplets; room temperature; energy saving; infectious diseases; disease transmission; particle dispersion; numerical simulation; flow patterns; pathogen inhalation; mixing ventilation; displacement ventilation.

DOI: 10.1504/WRSTSD.2013.050790

World Review of Science, Technology and Sustainable Development, 2013 Vol.10 No.1/2/3, pp.142 - 161

Received: 11 Nov 2011
Accepted: 27 Jul 2012
Published online: 28 Feb 2014 *

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