A comparison between thermophoresis and Brownian effects in thermal precipitation of micro- and nanoparticles

In this paper a comparison is carried out between thermophoresis and Brownian effects in the process of thermal precipitation. A numerical analysis is conducted to characterize the flowfield and particle transport and deposition in a typical thermal precipitator under forced convection condition. To evaluate the flowfield inside the device, steady and incompressible form of the 2-D Navier-Stokes equations are solved. For particles transport and deposition, a Lagrangian particle trajectory analysis procedure is used. Also, thermophoresis and Brownian effects are calculated by the Talbot model and a Gaussian white noise, respectively. The results show that thermophoresis plays a significant role in deposition of nano- and fine microparticles and makes the collection efficiency higher for finer particles. Also, interaction between thermophoresis and Brownian diffusion is found to be important in deposition process of nanoparticles.

کلیدواژه ها:

Thermophoresis ، Brownian diffusion ، Particle deposition ، CFD