Numerical studies of indoor airflow and particle dispersion by large Eddy simulation

The indoor airflow and contaminant particle concentration in two geometrically different rooms have been investigated using the Large Eddy Simulation (LES) technique based on Renormalization Group (RNG) theory derived by Yakhot, Orszag, Yakhot and Israeli, Journal of Scientific Computing, 1989. The first room is without contaminant particles. Its simulated air phase velocity profiles are validated against the measurements of Posner, Buchanan and Dunn-Rankin, Energy and Buildings, 2003. A good agreement is achieved between the prediction and measured data. The LES model successfully captures the mean flow trends as well as instantaneous flow information, which is required for appropriate design and evaluation of a ventilation system. The second room has contaminant particles, which are simulated with a Lagrangian particle tracking model. In this case, the LES model provides acceptable prediction of the contaminant particle concentration, compared to the particle concentration decay measured by Lu, Howarth, Adam and Riffat, Building and Environment, 1996. The numerical results reveal that the particle-wall impact model has a considerable effect on the Lagrangian concentration prediction. It is proposed that further improvements to the particle-wall impact model are required to correctly predict the contaminant particle concentration through the Lagrangian model.