Thermophoresis and the Brownian diffusion of nanoparticles in a flow reactor

The influence of thermophoresis and Brownian diffusion on deposition of the nanoparticles from a laminar gas flow on adsorbing walls of a flow reactor is investigated theoretically. Two similarity criteria characterizing the process of deposition of nanoparticles under nonisothermal conditions are formulated. It is shown that the influence of thermophoresis is significant only at the inlet area of the reactor, while Brownian diffusion acts over its entire length. To describe the interaction between the gas flow and the nanoparticles, the free-molecular approximation is used. The results of numerical calculations are given.