A frontal air intake may improve the natural ventilation in urban buses

In this report we analyze the air flow across the open windows (natural ventilation) of an urban bus model and the consequent dispersion of aerosols emitted in the passengers area. The methods include computational fluid dynamics simulations and three ways to characterize the dispersion of passive t...

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Bibliographic Details
Published in:	Scientific reports Vol. 12; no. 1; p. 21256
Main Authors:	Alexei Pichardo-Orta, F., Luna, Oscar Adrián Patiño, Cordero, J. Rodrigo Vélez
Format:	Journal Article
Language:	English
Published:	London Nature Publishing Group UK 08-12-2022 Nature Publishing Group Nature Portfolio
Subjects:	639/166 639/705 639/766 639/766/189 Aerosols Age Air flow Average flow Carbon dioxide Computer applications Fluid dynamics Humanities and Social Sciences Hydrodynamics Mathematical models multidisciplinary Science Science (multidisciplinary) Ventilation
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Summary:	In this report we analyze the air flow across the open windows (natural ventilation) of an urban bus model and the consequent dispersion of aerosols emitted in the passengers area. The methods include computational fluid dynamics simulations and three ways to characterize the dispersion of passive tracers: a continuous concentration-based model, a discrete random model and a parametric scalar based on the so-called mean age of air. We also conducted experiments using a 1:10 scale bus model and CO 2 as a passive tracer to assess the ventilation characteristics. We found that dispersion and expulsion of aerosols is driven by a negative pressure in the standard bus design equipped with lateral windows. Also, the average age of air is 6 minutes while the air flow promotes aerosol accumulation to the front (driver’s area). To speed up the expulsion of aerosols and reduce their in-cabin accumulation, we propose a bus bodywork prototype having a frontal air intake. All the numerical models and experiments conducted in this work agreed that the expulsion of aerosols in this novel configuration is significantly increased while the average age of air is reduced to 50 seconds. The average air flow also changes with the presence of frontal air intakes and, as a consequence, the expulsion of aerosols is now driven by a frontal velocity field.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	2045-2322 2045-2322
DOI:	10.1038/s41598-022-25868-x