Experimental investigation of scalar dispersion in indoor spaces
Experimental investigation of scalar dispersion in indoor spaces
The scalar dispersion from point sources in indoor spaces is experimentally investigated using simultaneous particle–image velocimetry and planar laser-induced fluorescence techniques in a 20:1 and a 60:1 full-to-model scale room model. The ventilation inlets dominate turbulence production, with magnitudes of the velocities and Reynolds stresses observed to increase with air changes per hour (ACH). Mean concentration maps show a dependence on the ACH and source location which is attributed to the flow field at the near-source region. The peak-to-mean concentration shows a weak dependence on the mean concentration and concentration variance maps, indicating risk for toxic chemicals may be underpredicted if based only on these information. The concentration PDFs are generally well-described by exponential distributions with C
99/c
rms
′ values never exceeding 5.0. The magnitudes of the advective and turbulent scalar fluxes are strongly dependent on the ACH and source location, neither of which are able to dominate the other by more than an order of magnitude. The eddy diffusivity tensor was measured and a conditional-averaging based method is proposed to approximate it to an isotropic eddy diffusion coefficient, K. For real applications where K is used to estimate magnitudes of the turbulent scalar flux using the gradient transport model, the assumption of isotropic turbulence can introduce an uncertainty of around 17.8%.
Eddy diffusivity, Indoor air quality, Indoor airflow, Risk assessment, Scalar dispersion
Lim, H.D.
3bec23a8-1475-4425-9101-1db28c371d1e
Foat, Timothy G.
0fa8d70b-8807-4f29-a0d9-885517bcd878
Parker, Simon T.
0776d677-58d7-4b65-ba63-a742cf4b947e
Vanderwel, Christina
fbc030f0-1822-4c3f-8e90-87f3cd8372bb
15 February 2024
Lim, H.D.
3bec23a8-1475-4425-9101-1db28c371d1e
Foat, Timothy G.
0fa8d70b-8807-4f29-a0d9-885517bcd878
Parker, Simon T.
0776d677-58d7-4b65-ba63-a742cf4b947e
Vanderwel, Christina
fbc030f0-1822-4c3f-8e90-87f3cd8372bb
Lim, H.D., Foat, Timothy G., Parker, Simon T. and Vanderwel, Christina
(2024)
Experimental investigation of scalar dispersion in indoor spaces.
Building and Environment, 250, [111167].
(doi:10.1016/j.buildenv.2024.111167).
Abstract
The scalar dispersion from point sources in indoor spaces is experimentally investigated using simultaneous particle–image velocimetry and planar laser-induced fluorescence techniques in a 20:1 and a 60:1 full-to-model scale room model. The ventilation inlets dominate turbulence production, with magnitudes of the velocities and Reynolds stresses observed to increase with air changes per hour (ACH). Mean concentration maps show a dependence on the ACH and source location which is attributed to the flow field at the near-source region. The peak-to-mean concentration shows a weak dependence on the mean concentration and concentration variance maps, indicating risk for toxic chemicals may be underpredicted if based only on these information. The concentration PDFs are generally well-described by exponential distributions with C
99/c
rms
′ values never exceeding 5.0. The magnitudes of the advective and turbulent scalar fluxes are strongly dependent on the ACH and source location, neither of which are able to dominate the other by more than an order of magnitude. The eddy diffusivity tensor was measured and a conditional-averaging based method is proposed to approximate it to an isotropic eddy diffusion coefficient, K. For real applications where K is used to estimate magnitudes of the turbulent scalar flux using the gradient transport model, the assumption of isotropic turbulence can introduce an uncertainty of around 17.8%.
Text
1-s2.0-S036013232400009X-main
- Version of Record
More information
Accepted/In Press date: 4 January 2024
e-pub ahead of print date: 6 January 2024
Published date: 15 February 2024
Additional Information:
Publisher Copyright:
© 2024 The Authors
Keywords:
Eddy diffusivity, Indoor air quality, Indoor airflow, Risk assessment, Scalar dispersion
Identifiers
Local EPrints ID: 486281
URI: http://eprints.soton.ac.uk/id/eprint/486281
ISSN: 0360-1323
PURE UUID: b34b542d-923c-4dd9-9350-3e22725e3e5a
Catalogue record
Date deposited: 16 Jan 2024 17:43
Last modified: 20 Apr 2024 01:54
Export record
Altmetrics
Contributors
Author:
H.D. Lim
Author:
Timothy G. Foat
Author:
Simon T. Parker
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics
