(281h) DNS of the Velocity and Temperature Fields in a Small Room

This talk presents the results of a numerical study of the velocity and temperature fields in a model of a small room containing a seated mannequin. Results are also presented for the trajectories and ultimate fate of small particles that are introduced through the air inlet. The study was motivated by an experimental study carried out by Professor M. Glauser's group at Syracuse University. In the experimental study, air entered the room through a floor vent and exited through a ceiling vent on the other side of the room. A table was placed in front of the floor vent, and a mannequin was seated at the table. The mannequin could be electrically heated so that its surface temperature was 37C. Velocity and temperature measurements were carried out at several points and flow visualization experiments were conducted. It was noted that, if present at all, turbulent fluctuations were small.

The objective of the simulations was to obtain a more detailed understanding of the flow in the room. Of specific interest were the effects of the table, chair, and mannequin on the ultimate fates of small particles that were introduced into the room with the air in the inlet. The importance of the thermal plume around the mannequin was of particular interest since the thermal plume plays a role in transporting particles from near the floor to the breathing zone and may also prevent particles from reaching the breathing zone from above.

The simulations were performed with a single phase version of a lattice Boltzmann method (LBM) that was originally developed for two-phase flows by Inamuro et al. (J. Comp. Phys. 198, 628-644, 2004). The method has the advantages of simplicity comparable to the widely used BGK LBM and stability at much higher Reynolds numbers than may be achieved with the BGK LBM. Particle trajectories were computed by integrating a particle equation of motion that included aerodynamic drag and gravity. The one-way coupling assumption was invoked since the particles ranged in size from 2 to 16 micrometers and their concentration was dilute.