CUED Publications database

Pollutant flushing with natural displacement ventilation

Hunt, GR and Kaye, NB (2006) Pollutant flushing with natural displacement ventilation. Building and Environment, 41. pp. 1190-1197. ISSN 0360-1323

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We examine the time taken to flush pollutants from a naturally ventilated room. A simple theoretical model is developed to predict the time taken for neutrally-buoyant pollutants to be removed from a room by a flow driven by localised heat inputs; both line and point heat sources are considered. We show that the rate of flushing is a function of the room volume, vent areas ( A ) and the distribution, number (n) and strength (B) of the heat sources. We also show that the entire problem can be reduced to a single parameter ( μ) that is a measure of the vent areas, and a dimensionless time ( τ) that is a function of B, V and μ. Small-scale salt-bath experiments were conducted to measure the flushing rates in order to validate our modelling assumptions and predictions. The predicted flushing times show good agreement with the experiments over a wide range of μ. We apply our model to a typical open plan office and lecture theatre and discuss some of the implications of our results. © 2005 Elsevier Ltd. All rights reserved.

Item Type: Article
Divisions: Div A > Fluid Mechanics
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:12
Last Modified: 22 May 2018 07:38