Motion of a dusty gas at the entrance to a flat channel and a circular pipe

Abstract

It is shown that at large Reynolds numbers, calculated from the entrance velocity and the half-width of the channel, four characteristic flow regions are formed in the entrance section. The equations describing the motion of the mixture in each of these regions are constructed by the method of matched expansions. An expression relating the particle concentration distribution at points remote from the entrance section to the particle concentration distribution in the boundary layer on a flat plate at points remote from the beginning of the plate is obtained. The dependence of the dispersed-phase concentration profile formed on the governing parameters is studied on the basis of a numerical solution. It is shown that as the contribution of the Saffman force to the interphase momentum transfer increases, the rise in particle concentration in the direction of the wall is replaced by a fall. A qualitative correspondence between the calculated particle concentration profiles and certain known experimental data is noted.