Nanoparticle Knudsen layers in gas-filled microscale geometries.
Nanoparticles suspended in ambient air within microscale geometries form a Knudsen layer when diffusing in a Brownian fashion toward a solid wall. More specifically, the particle number density adjacent to the wall approaches a nonzero value proportional to the flux. An approximate theory for the coefficient of proportionality as a function of the particle sticking fraction at the wall and the drift velocity normal to the wall is compared to Langevin particle simulations. The resulting boundary condition enables accurate advection-diffusion simulations of nanoparticle-aerosol transport.
Gallis
M A
MA
Engineering Sciences Center, Sandia National Laboratories, Albuquerque, NM 87185-0346, USA.
Torczynski
J R
JR
Rader
D J
DJ