O. B. Kudryashova

Remote Optical Diagnostics of Nonstationary Aerosol Media in a Wide Range of Particle Sizes

Polydisperse gas flows with condensed particles suspended therein are widely spread in nature and play an important role in many branches of the modern engineering and technology. There is a necessity for estimating parameters of disperse media in the manufacturing processes, scientific research, and atmosphere sounding. In industry, the result of this estimation can be employed as the quality measure of a product. When designing and distributing multi-phase systems to study the processes of controlling their parameters, it is also needed to determine values of the quantities characterizing such systems.

Experimental study of the processes of aerosol transformation under ultrasonic impact

We studied the evolution of dispersion characteristics and aerosol concentration during its deposition under high-frequency ultrasonic impact. It is found that the average volume-surface diameter of aerosol (water, flour, and smoke) particles depends on time. It is shown that, when impacted by ultrasonic oscillations, a coarsely dispersed aerosol undergoes accelerated deposition by particle coagulation; and the larger the particles of the initial aerosol, the greater this acceleration.

A Method for Laser Measurement of Disperse Composition and Concentration of Aerosol Particles

A modified method of small-angle scattering that consists in solving a series of direct problems in aerosol optics is proposed to obtain a function of particle size distibution; a modified method of spectral transperancy is employed to determine the concentration of particles in a cloud. A measurement system comprising radiator (helium-neon laser), photodetector and recording instruments has been developed. Measurements in aerosol clouds are performed.

Ultrasonic effect on the penetration of the metallic melt into submicron particles and their agglomerates

Deagglomeration and wetting of submicron particles in a metal melt under ultrasonic exposure are considered based on the theory of acoustic cavitation and capillary phenomena. Basic dependences linking the exposure time with physicochemical properties of the particles and the melt, as well as with acoustic radiation characteristics, are found. The experimental and calculated times of ultrasonic treatment of the aluminum melt containing submicron aluminum oxide particles are compared, and a satisfactory agreement of results is found.

Ultrasonic impact on a metal melt containing electrostatically charged nanoparticles

Ultrasonic processing is applied to modify nanopowders of metals for the creation of composition alloys. The introduction of particles to metal is prevented by their low wettability in the metal melt. We use electrostatic charging of particles to increase the wettability of particles and to prevent their agglomeration. Mechanisms of the ultrasonic impact on melts of metals containing charged nanoparticles are considered. We find that an electric charge of the surface leads to a decrease in the contact angle. Expressions for the time of ultrasonic processing depending on physical and chemical characteristics of particles and the melt are found.

Ultrasonic dispersion of agglomerated particles in metal melt

This work considers the deagglomeration and wettability of particles by metal melt and proposes a mechanism of particle agglomerate dispersion by ultrasonic cavitation. The main dependences connecting the processing time and intensity with the physical and chemical properties of particles and the melt as well as acoustic parameters are obtained. For the first time found that melt during ultrasonic treatment, inclusive the particles agglomerates proportional to melt viscosity and the size of the agglomerates. It has been established that time ultrasonic treatment melt containing the particles agglomerates is proportional to melt viscosity and the size of the agglomerates. The required time for successful melt infiltration in the agglomerates, wettability and their introduction into the melt takes ten minutes. The suggested equation allows estimating the intensity of ultrasonic radiation, required to destroy the agglomerates of particles in the melt. It was found that intensity of the ultrasound must be inv...