Unipolar Charging Research Articles

Unipolar diffusion charging of aerosols and the image force

Unipolar diffusion charging of aerosols and the image force

Noncontinuum Unipolar Charging of Aerosols: The Role of External Electric Fields

An approximate theory is developed for the charging by heavy ions of submicron aerosol particles in external electric fields. The theory proceeds from a nonintuitive basis established by kinetic theory and reproduces the general features found in the relevant experimental data.

On the stochastic nature of the acquisition of electrical charge and radioactivity by aerosol particles

The distributions of charge and radioactivity in an aerosol arising from the stochastic nature of the acquisition processes are discussed. Three illustrations are given. The electrical charge distribution resulting from the unipolar diffusion charging of a monodisperse aerosol is derived. The kinetics of the adsorption of radioactive iodine and RaA on a monodisperse aerosol and the resultant distribution of radioactivity are described.

Electrical measurement of the mass concentration of a self-preserving aerosol size distribution.

Recently fifty-eight measurements of urban aerosol size distributions by Clark have shown that these distributions agree quite well with the self preserving form proposed by Friedlander within the size range of 0.05 to 5 microns radius. This paper shows that for an aerosol obeying the self preserving distribution model, the volume concentration (and, hence, the mass concentration for constant density) is directly proportional to the electric current collected when the aerosol is unipolarly charged, passed through a weak electric field to remove particles smaller than 0.05 micron and then collected by a current collector. It is shown that the linear relation between the mass concentration and collected current is independent of the unipolar charging method used. A test of this theory using Clark’s electric counter data was encouraging and suggests that the electric measurement of urban aerosol mass concentrations by properly designed instruments may be feasible.

Aerosol rarefaction studies.

Abstract An experimental study was carried out to study the relative stabilities of charged and uncharged aerosols. The clouds differed in that charged aerosol had been passed through a DC corona. The aerosol was continuously generated at a point in a low-velocity wind tunnel in which relative cloud and tunnel dimensions practically eliminated wall effects. Aerosol cloud dimensions were determined at several distances downwind from the point of generation for both charged and uncharged aerosols. The rarefaction phenomenon produced as a result of the unipolar charging was measured for both positive and negative corona. The relative effects are noted. The point at which aerodynamic effects predominate over electrostatic effects is noted. The several forces affecting the interparticle spacing are considered in explaining the phenomena noted in these experiments.