Publication date: June 2017
Source:Building and Environment, Volume 118
Author(s): T.G. Foat, J. Nally, S.T. Parker
Understanding mixing times for transient pollutants in mechanically ventilated rooms is important for resilience and safety planning for accidental releases of toxic material. There is a lack of information on the ability of simple models available to predict these times for ventilated spaces with different geometries and ventilation configurations. Three analytical mixing time models, including a novel jet transit based approach, have been selected for comparison with computational fluid dynamics (CFD) predictions for a wide range of cuboidal rooms with ceiling ventilation. A modelling tool has been developed, using open source and open source based software, to automatically build and run a large number of Reynolds averaged Navier-Stokes CFD models. The tool has been used to study the dependence of the chosen mixing metrics on room geometry and ventilation parameters, such as the air change rate, for a transient pollutant entering the room via the ventilation system. The room volume, shape, air change rate and vent layout were varied for each room using a Sobol sequence experimental design. The CFD tool has been used to assess the validity of the analytical mixing time models and to derive parameters for the scenarios of interest.
![image]()
Source:Building and Environment, Volume 118
Author(s): T.G. Foat, J. Nally, S.T. Parker
Graphical abstract
