METHOD OF DETERMINING DISPERSITY AND CONCENTRATION OF PARTICLES IN AEROSOL CLOUD Russian patent published in 2012 - IPC G01N15/02 

FIELD: physics.

SUBSTANCE: method of determining dispersity and concentration of particles in an aerosol cloud is based on measuring attenuation of a parallel beam of probing optical radiation. Spectral transmittance is measured in the wavelength range of probing optical radiation λ=(0.3-1.1) mcm. Radiation intensity is measured with time resolution of not more than 0.01·Δt (where Δt is the characteristic time of change of the size of the aerosol cloud). Optical length and volume of the cloud is determined using high-speed video recording carried out in not less than two aspect angles. Dispersity of aerosol particles is determined by solving the inverse problem for the equation:

and concentration of aerosol particles is determined using formulae:

where λ is the wavelength of the probing optical radiation; τ(λ,t)=ln[l/T(λ,t)] is the spectral optical density of the aerosol cloud; T(λ,t)=[J(λ,t)/J₀(λ)] is spectral transmittance; J(λ,t), J₀(λ) is intensity of probing optical radiation passing through and incident on the aerosol cloud; C_n(t), C_m(t) is the calculated and mass concentration of aerosol particles; l(t) is optical length; Q[α, m(λ)] is the efficiency factor of attenuating aerosol particles; α=πD/λ is the diffraction parameter; D is the diameter of aerosol particles; D_max, D_min is the maximum and minimum particle diameter, presence of which is possible in the aerosol cloud; f(D, t) is the differential function of the calculated distribution of aerosol particles according to size, which characterises their dispersity; m(λ) is the relative complex refractive index of the material of the aerosol particles; M is the mass of the sprayed substance in the aerosol cloud; V(t) is the volume of the aerosol cloud; ρ is the density of the material of aerosol particles.

EFFECT: high accuracy and information content, wider range of using the spectral transparency method.

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