Aerosol Aspiration

 

Flowing aerosol droplets deviate from the fluid streamlines due to droplet inertia, which is introduced via an induced drift velocity in the Eulerian-Eulerian framework adopted in AeroSolved. In order to validate the drift modeling inside the AeroSolved code, we simulate aerosol aspiration inside an aerosol sampler that operates on a velocity different than the ambient velocity flow. The sampler velocity ratio R is defined as the sampling velocity over the ambient velocity. We simulate at R = 5, for a range of droplet sizes resulting from Stokes numbers St=0.01 to St=5. We compare our simulation results against the semi-empirical model of Belyaev & Levin (1974) for aerosol aspiration. The validation case can be executed by calling the following scripts for preparation, running and post-processing: prep.sh, run.sh (will take a long time) and post.sh. The post.sh script requires Python with Matplotlib to be installed, and creates plot.pdf (see below), which shows the aspiration efficiency A (i.e., the ratio of that what is actually sampled over that what ‘should’ have been sampled if droplets would follow the streamlines) as a function of the Stokes number for both the simulation and Belyaev & Levin model. Good agreement in terms of aspiration efficiency A is established.

plot