Roman N. Golykh

Ultrasonic radiators for the action on gaseous media at high temperatures

The article is devoted to the study of influence of high temperature on the operation of the ultrasonic disk radiator intended for generation of high-intensity vibrations in gaseous media. As a result of researches it was determined, that temperature increase of gas and the radiator led to the rise of vibration amplitude of the surface of the disk radiator and the fall of level of acoustic pressure owing to the reduction of gas density.

Increase of separation efficiency in the inertial gas-purifying equipment by high-intensity ultrasonic vibrations

This article describes the prospects of applying of ultrasonic vibrations to increase efficiency of gas-dispersed flow separation on the example of the vortex tube. Developed model of the separation of gas-dispersed flow containing solid particles is described. The specific feature of the model is in consideration of particle coagulation caused by high-intensity ultrasonic vibrations. The characteristics of the gas flow and ultrasonic influence providing minimum separation time of solid fine particles and continuous phase are determined.

Theoretical study of acoustic coagulation of gas-dispersed systems

The mathematical model of the process on the macroscopic level considering viscosity of gas medium has been proposed for the analysis of acoustic coagulation of solid and fluid particles in gas media. The article presents the results of theoretical calculations, which allow determining the dependences of coagulation velocity at the different initial particle concentration on the parameters of acoustic influence (intensity, frequency). As a result of the investigation high efficiency of application of acoustic vibrations with the frequencies lying in the ultrasonic range for coagulation of fine aerosol (up to 5 µm) is shown.

Method for calculation of optimum intensity of cavitation influence on viscous and fine-dispersed liquid media

The article is devoted to the new approach to acceleration of technological processes in viscous and fine-dispersed media due to the influence of high-intensity ultrasonic vibrations, which provides formation of cavitation. It is shown that the existing method for calculation of required power of the ultrasonic technological devices cannot be used for designing special equipment intended for processing of high-viscosity and fine-dispersed liquid media. The improved method for calculation of necessary intensity of ultrasonic influence is proposed. In this method cavitation mode takes place in viscous and fine-dispersed media in order to reveal required power operating conditions of the ultrasonic electronic generators. The obtained results allows recommending the choice of optimum intensity (up to 30 W/cm2) of the ultrasonic influence in liquids with the viscosity of up to 0.6 Pa·s (oil, glycerin, epoxy resin and others), which are widely used in the practice.

Determination of ultrasonic effect mode providing formation of cavitation area in high-viscous and non-Newtonian liquids

The article presents the phenomenological model of the formation of cavitation area in high-viscous and non-Newtonian liquids. Proposed model is based on the study of the formation of cavitation area as a whole but taking into account the main effects and phenomena occurring inside this area. The analysis of the model allows revealing optimum intensities of the ultrasonic influence, which are necessary for the appearance of the mode of developed cavitation for liquids different in their rheological properties. The analysis of the model lets determining, that optimum intensities of the influence for the most of liquids does not exceed 40 W/cm2 at the frequency of 22 kHz, with the exception of dilatant fluids, for which intensity of influence can achieve 100 W/cm2. As a result of the model analysis it is found out the change of optimum intensity for non-Newtonian liquids with the course of time induced by the relaxation of viscosity. Increase or decrease of the intensity, which is necessary for the formation of cavitation area, achieves 20 W/cm2. Obtained results can be applied for the choice of power modes of the ultrasonic technological equipment and the control of the process of cavitation treatment of media with different rheological properties.

The control of the ultrasonic coagulation of dispersed nanoscale particles

In the article the results of the researches on efficiency definition of ultrasonic coagulation of ready nanodispersed product are presente. Developed measuring bench allowed to control changes of concentration of nanoparticles due to their agglomeration at the application of high-intensity ultrasonic vibrations.

Study of the process of liquid atomization from the ultrasonic disk radiator

The article is devoted to the process of liquid spraying by the ultrasonic radiator in the form of disk. New functional possibilities of the ultrasonic disk radiators during liquid spraying were studied. The results of productivity and power inputs for spraying at the application of different systems of fluid supply were obtained.

Revelation of optimum modes of ultrasonic influence for atomization of viscous liquids by mathematical modelling

In the article the process of cavitation low-frequency (up to 250 kHz) ultrasonic atomization of viscous liquids in a layer is investigated. It takes place with entering of acoustic energy to working zone through liquid. To reveal optimum modes of ultrasonic influence depending on physical properties of atomized liquid (viscosity, surface tension, etc.) the model describing stepwise transformation of mechanical vibration energy of ulrtasonic frequency into energy of capillary waves providing the formation of drops was proposed and developed. For the first time we offer theoretical explanation of essential dependence of drop diameter on vibration amplitude of spraying surface based on changes of mean thickness of ridges of capillary waves according to their amplitude due to occurence of nonlinear effects. Obtained results can be a base for the design of specialized ultrasonic atomizers of liquids with high viscosity for the formation of aerosols with specified productivity and dispersed features.

Process modeling of cavitation zone in process vessels with high-viscous and fine-dispersed liquid media

The article presents the results of theoretical investigations aimed at revealing possibilities of providing maximum size of cavitation zone in limited vessels during ultrasonic impact technological media having high viscosity or high concentration of dispersed phase. In order to find out optimum conditions (geometrical dimensions and forms of process vessel) and modes (intensity) of ultrasonic impact on liquids different in viscosity and acoustic properties, the mathematical modeling was carried out for dynamics of the cavitating medium. The proposed approach to the modeling is based on numerical steam-gas-liquid medium developed on the well-known models of microscopic process of extension and collapse of single cavitation bubble. The obtained results allow recommending choice of specialized process vessels and optimum intensities of impact.

Effciency increase of the dust-extraction plant by high-intensity ultrasonic action

The article presents the results of the studies aimed at the ways of efficiency increase of the dust-extraction unit operation on the base of Venturi pipe due to action of high-intensity ultrasonic vibrations. Carried out theoretical analysis of dust-extraction unit operation let determine the possibility of efficiency increase and dust reduction of gas at the output of the plant at the application of ultrasonic action.