Sergey S. Khmelev

Ultrasonic oscillating system for radiators of gas media

In article the new construction of the multiple-unit piezoelectric transducer with the increased output power and a disk radiator, which has a refined thermal mode is offered. The designing procedure of bending vibration disk radiators is described. The developed constructions are implemented; their technical characteristics and functionality are explored.

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.

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.

The development of experimental sample of ultrasonic equipment for the intake of lunar soil

The article is devoted to the development of experimental sample of ultrasonic equipment for carrying out investigations on drilling of the simulator of lunar soil. Carried out studies show possibility in principle of drilling of the simulator (intake) of lunar soil at application of ultrasonic vibrations on working tool.

Increase in efficiency of processes through optimization of ultrasonic vibrating system consisting of half-wave modules of variable cross-section

In this paper the tendencies, which allow creating and applying piezoelectric transducers with enlarged radiation surface in order to increase efficiency of ultrasonic technological devices, are analyzed.

Efficiency increase of multi half-wave radiators

The article presents the results of the studies aimed at the efficiency increase of the piezoelectric vibrating systems with multi half-wave radiators made in the form of the bar with variable diameter. It is determined, that the change of the form of junction between the parts of different diameters of the radiator essentially influences on the efficiency of ultrasonic radiation in liquid media.

Rules and features of the design of piezoelectric sources of high-intensity ultrasonic action

In the article the rules and consequence of the design of separate units (piezoelectric transducers, boosters, concentrators and working tools) at the production of piezoelectric vibrating systems - sources of ultrasonic action on different technological processes are introduced. Proposed rules provide the development of the ultrasonic vibrating systems with necessary parameters of ultrasonic action, such as power, intensity of radiation, frequency, radiating surface, diraction of radiation, etc.

Development of equipment for fine-dispersed atomization of viscous liquids

The article considers new technology of atomization of viscous liquids from unsteady surface with next additional atomization in spray-type needle moving out aerosol flow was considered. As a result of the researches, high efficiency of realization of secondary atomization was proved and dependences of atomization efficiency on frequency, vibration amplitude and form of the end of spray-type needle were developed. The obtained results of atomization of viscous liquids are evidence of reducing of particles of primarily sprayed aerosol by 3–4 times.

Study of efficiency of ultrasonic treatment in running volumes

The article presents the results of studies allowing us to reveal the operation condition of the ultrasonic apparatuses with multi half-wave radiators in confined space, at which efficiency of ultrasonic influence on the technological process decreases and essential deviation from nominal operation mode is observed.