Turbulent flow of aerosol in rotating channels of turbomachines

Rotary separators are used for removal of suspended solid particles from the gas stream in rotating channels of a turbomachine. The aerosol is first precipitated and coagulated on the channel surfaces by action of centrifugal and Coriolis forces, then driven to the periphery of the runner for subsequent extraction. The effectiveness of this process in long narrow rotating channels depends on the turbulence of flow. For an evaluation of the separator performance, the turbulent flow of an aerosol in backward slanted rather than radial channels is described by the equation of a cyclon, analogus to that for centrifugal dust trap, with the appropriate boundary conditions. Attenuation of external turbulence along a channel and turbulent diffusion are accounted for by corresponding mass transfer coefficients, the latter determined from the condition of continuity for the gas and the momentum equation in accordance with the semiempirical theory. An expression is obtained for the efficiency of such a separator on this basis and another one is obtained from the equation of trajectories without turbulence, both involving geometrical parameters of the system and thus useful for design purposes.