The role of boundary conditions in the theory of aerosol particle thermophoresis

The force affecting a macroscopic particle in an inhomogeneously heated gas under conditions of a near free molecular regime is calculated on the basis of the solution of the kinetic equation. As a boundary condition, an integral relation is used that relates the distribution functions of the velocities of molecules reflected and incident on the particle through the scattering kernel. Quantitative calculations of the thermophoretic force are carried out with the use of different known scattering kernel models. By comparing the developed theory with experimental data, the reliability of these scattering kernels is analyzed and the values of their accommodative parameters are determined.