Experimental study of the effect of turbulent diffusion on precipitator efficiency

The Deutsch model for calculating particle collection in an electrostatic precipitator assumes uniform particle concentration profiles and thus infinite mixing by the turbulent flow. Recent theories which treat the mixing as finite, thus allowing for the formation of nonuniform particle concentration profiles, predict efficiencies far in excess of Deutsch predictions for low turbulence conditions. In this paper optically determined in situ particle concentration profiles in a parallel plate precipitator are presented and compared with the predictions of these newer theories. Experiments were designed so as to permit separate control and precise measurement of the degree of turbulence and particle mobility in the precipitator. The measurements enable a critical assessment of these new theories to be made. It is concluded that the convective diffusion equation adequately describes particle transport in the collection stage of a two-stage parallel plate precipitator.