Relevance. Ultrasonic atomization is widely used in many areas of industry for processing liquid media and melts into particles of a given size, safe disposal of gas waste, and spray drying. The feasibility of using ultrasonic atomization is due to the possibility of obtaining fine particles of a monodisperse composition with minimal energy costs compared to other atomization methods. Since atomization is carried out by feeding a liquid medium onto a surface oscillating at an ultrasonic frequency, it is necessary to form on this surface the maximum amount of liquid placed in a layer of the optimal thickness for atomization. To ensure maximum productivity, it is not enough to feed the sprayed liquid onto the surface through one channel, and increasing its diameter does not solve the problem due to the impossibility of distributing a large amount of liquid on the surface around one feed channel with the optimal thickness. Aim is due to the need to ensure the supply of liquid onto the oscillating surface through multiple channels on this surface in order to ensure the highest possible atomization performance without increasing the size of the resulting droplets. Methods. The paper proposes a method for calculating the shape of the spray surface and the distance between the holes through which liquid is supplied to the oscillating surface to ensure a given spray performance. Results and Conclusions. The work resulted in an experimental determination of the dependence of the liquid spreading radius R0 on viscosity and surface tension. It was found that with an increase in viscosity, the liquid spreading radius decreases and an increase in the oscillation amplitude is required for spraying. With a decrease in the surface tension coefficient, the liquid spreading radius R0 increases, and the oscillation amplitude for spraying can decrease. The proposed and developed method, as well as certain numerical values ​​of the R0 parameter, made it possible to design an ultrasonic atomizer of liquid media with the formation of sprayed droplets with an average diameter of no more than 65 μm, with a productivity of more than 15 ml / s at a total power consumption of less than 150 VA. For citation: Khmelev V.N., Shalunov A.V., Terentiev S.A., Genne D.V. Ensuring the specified productivity of liquid media ultrasonic atomization. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering, 2026, vol. 337, no. 7, pp. 16-24. https://doi.org/10.18799/24131830/2026/7/5223

The study explores the feasibility of enhancing the impact of ultrasonic vibrations on liquid media at elevated temperatures. To intensify processes at the gas-liquid interface through ultrasonic cavitation at temperatures of up to 60-75 degrees C, the functional capabilities of the equipment were investigated. It is shown that generator output parameters must be matched with the oscillatory system, factoring in temperature-induced changes in the medium's properties to ensure maximum ultrasonic impact. The study of how elevated temperatures affect key equipment parameters helped to establish the optimal matching modes between the generator and the ultrasonic oscillatory system. This enables the application of ultrasonic technology to improve process efficiency in both laboratory and industrial settings. Empirical results confirm that the gas-liquid interfacial area in viscous media can be increased by reducing the attenuation of capillary waves as the temperature rises. The findings validate the practical application of ultrasonic technologies as an intensifying factor at elevated temperatures. This approach ensures maximum intensification of processes occurring in liquid media during cavitation at temperatures of 55-75 degrees C and intensities startingfrom 15 W/cm(2), which opens new prospects for optimizing technological processes.

The article provides the results of studies and developments aimed at addressing the problem of smoke deposition (coagulation) in order to increase the efficiency of fire suppression (detection of ignition source) and ensure the evacuation of people from the smoke generation center. The possibility and efficiency of affecting smoke with mechanical oscillations of ultrasound frequency with the high level of sound pressure able to implement the process of acoustic coagulation, i.e., merging solid particles with the subsequent deposition, have been considered. For the practical implementation of smoke deposition and elimination of flaws in the existing ultrasonic exposure, specialized ultrasonic equipment with improved performance characteristics and reduced overall dimensions has been designed, developed, and manufactured. The practical use of the developed ultrasonic emitter weighing less than 1 kg ensured the ultrasonic exposure with a sound pressure level of 148–149 dB at the frequency of 22,5 kHz. The performed tests confirmed the high efficiency of the developed ultrasonic emitter during the deposition of smoke generated within the process of wood combustion. The tests have also indicated the potential improvement in smoke deposition efficiency by sound pressure increase and helped to outline the areas of further research.

Relevance. The lack of effective, safe and environmentally friendly methods for settling suspended solid particles and smoke in processes related to the extraction, transportation and processing of minerals, and fire extinguishing. Aim. Development and research of a dual-frequency ultrasonic emitter system to improve the efficiency of settling hazardous dust and smoke suspensions. Methods. Experimental studies aimed at obtaining data for constructing radiation patterns, calculating the linear attenuation and acoustic power of ultrasonic emitters. Results and conclusions. The authors have developed the ultrasonic disk emitters, consisting of a piezoelectric modernized transducer, made according to the Langevin design scheme and a bending-oscillating emitter, equipped with reflectors, phase-aligning cones and horns. They developed the experimental stand, consisting of two simultaneously operating ultrasonic disk emitters with close natural resonant frequencies and a sound pressure meter. It was shown that the use of reflectors increased the total sound pressure of two ultrasonic emitters by 3–3.5 dB. The angle of the main lobe of the directivity pattern was ±7.5 degrees. The use of phase-aligning cones ensured the formation of acoustic oscillations in one phase from oscillating surfaces in different phases and increased the sound pressure of the system by 8–9 dB. When two ultrasonic emitters simultaneously act on the air environment, a zone of occurrence of beats at a low frequency of acoustic oscillations (300 Hz) is formed, while the sound pressure reaches 97.6 dB at a distance of 1 m and 77.1 dB at a distance of 20 m. It was established that the sedimentation of cement dust occurs at least 300 times faster than with natural sedimentation, and less than 50 times faster than with the implementation of the effect of one disk emitter of the same area. The time of action required for the sedimentation of smoke arising from the combustion of pine sawdust did not exceed 10 seconds to establish a visibility range of at least 10 m.

The article is devoted to the study of the process of particle agglomeration in cross ultrasonic fields. It has been established that to achieve high efficiency of particle agglomeration, it is most effective to carry out comprehensive ultrasonic exposure using a tubular emitter and two longitudinally oscillating emitters installed at the ends. At the same time, to control the structure of the generated acoustic field and change the centers of coagulation of particles, it is proposed to carry out periodic exposure to a tubular emitter in two modes of vibration (bending-radial and radial). To retain particles during switching of oscillation modes, ultrasonic exposure is carried out with a longitudinally oscillating emitter. This ensures a degree of coarsening of 15 at a concentration of 1.8 g/m3.

This study explores the challenges associated with dispersing disinfectant liquids for sanitizing individuals, indoor spaces, vehicles, and outdoor areas. Among the various approaches, fine aerosol sprays with a high particle surface area emerge as a particularly promising solution. Ultrasonic spraying, which leverages diverse mechanisms of ultrasound interaction with liquids, offers several distinct advantages. Notably, it enables the production of fine aerosols from liquids with a broad range of physical and chemical properties, including variations in purity, viscosity, and surface tension. This capability is especially critical for disinfectant liquids and suspensions, which often exhibit low surface tension and/or high viscosity. The article provides a comprehensive review of ultrasonic spraying methods and technologies developed by the authors’ team in recent years. It highlights innovative ultrasonic sprayers, including the latest designs, which are capable of generating aerosols with precise dispersion characteristics and high productivity from disinfectant liquids.

The article is devoted to the study of ultrasonic agglomeration of PM 2.5 in homogeneous and inhomogeneous ultrasonic fields. The possibility of increasing the efficiency of ultrasonic agglomeration by initiating acoustic streams in a resonant inhomogeneous ultrasonic field is shown. A inhomogeneous ultrasonic field with zones of high and low sound pressure levels formed using a bending-oscillating disk transmitter made it possible to initiate acoustic vortex-type streaming that promotes the movement of particles into the nodal areas of a standing wave and between them. Due to the formation of a inhomogeneous ultrasonic field, the efficiency of particle collection is increased: for PM 2.5, the efficiency reaches 95%; PM 1.5—92%; PM 0.5—85%. The results were obtained under the following conditions: concentration 2 × 10−2 g/m3, sound pressure level 165 dB, flow rate 6.2 m3/h. For comparison, when a homogeneous ultrasonic field is formed in the agglomeration chamber (under similar conditions), the efficiency of particle capture by inertial gas cleaning equipment does not exceed the following: for PM 2.5—89%; PM 1.5—85%; and PM 0.5—76%. The obtained research results made it possible to propose a design for an agglomeration chamber that can greatly increase the productivity of ultrasonic flow processing.

The article is devoted to investigation of energy-efficient moisture removal from capillary-porous materials. Moisture is removed by dispersion at collapse of cylindrical cavitation bubbles, formed by ultrasonic vibrations in the capillaries of the material. Mathematical model, which allowed to investigate the mechanism of moisture dispersion, has been developed. Necessity of realization of cavitation bubble full life cycle in capillary (slow growth, rapid expansion with deformation, collapse) was found. An optimal range of sound pressure levels from 150 dB ("critical level" at which dispersion of water from capillary starts) up to 170 dB (dispersion productivity growth stops due to cavitation bubbles reaching maximum size equal to diameter of capillary) was determined. It is shown that the size of the dewatered sample for maximum drying efficiency should correspond to the ultrasonic wavelength in air. Ultrasonic dispersion of liquid during drying was confirmed experimentally. It is found that for significant reduction of drying time (up to 50% and more) it is necessary to affect in the range of 165-170 dB. And the materials to be dried must be placed as particles or layers having dimensions or thicknesses corresponding to the length of the ultrasonic wave in air. The implementation of ultrasonic drying, on the example of food products (beets) provided a reduction in drying time of 1.9 times, while reducing energy costs by 1.7 times in comparison with convective drying.

The analysis conducted herein has shown that the efficiency of smoke precipitation can be improved by additionally making smoke particles interact with ultrasonic (US) oscillations. Because the efficiency of US coagulation lowers when small particles assemble into agglomerates, the authors of this work have suggested studying how smoke particles interact with complex sound fields. The fields are formed by at least two US transducers which work at a similar frequency or on frequencies with small deviations. To form these fields, high-efficiency bending wave ultrasonic transducers have been developed and suggested. It has been shown that a complex ultrasonic field significantly enhances smoke precipitation. The field in question was constructed by simultaneously emitting 22 kHz US oscillations with a sound pressure level no lower than 140 dB at a distance of 1 m. The difference in US oscillations’ frequencies was no more than 300 Hz. Due to the effect of multi-frequency ultrasonic oscillations induced in the experimental smoke chamber, it was possible to provide a transmissivity value of 0.8 at a distance of 1 m from the transducers and 0.9 at a distance of 2 m. Thus, the uniform visibility improvement and complete suppression of incoming smoke was achieved. At the same time, the dual-frequency effect does not require an increase in ultrasonic energy for smoke due to the agglomeration of small particles under the influence of high-frequency ultrasonic vibrations and the further aggregation of the formed agglomerates by creating conditions for the additional rotational movement of the agglomerates due to low-frequency vibrations.

In this paper a new approach to increase the agglomeration efficiency of finely dispersed aerosols by generating toroidal vortex streams in inhomogeneous ultrasonic field is proposed and studied. From the obtained experimental results (for two types of emitters) it could be established that the toroidal vortex streams generated in an inhomogeneous ultrasonic field provide an increase of the agglomeration efficiency when exposed to a gas-dispersed flow injected into the agglomeration chamber at a speed of up to 0.2 m/s. Further increase of the injected flow velocity leads to disruption of the structure of the generated vortex streams and agglomeration efficiency decreases.In the course of the analysis, it was found that the efficiency of agglomeration by toroidal vortex streams increases in direct proportion to the increase of the sound pressure level up to 165 dB. After that, no further increase in agglomeration efficiency is observed.By analyzing the agglomeration efficiency depending on particle size, it was possible to verify that the efficiency of agglomeration in comparison with agglomeration in a homogeneous ultrasonic field for droplets with a size of 0.2 … 0.6 μm is increased by 25 %, for 1.8 μm droplets by 20 %; and for droplets larger than 2.5 μm, the increase in efficiency is no more than 17 %.

The particles of micron and submicron sizes (PM 2.5 and less) in gas environments pose a significant danger to humanity due to the emergence of specific and very dangerous diseases of the cardiovascular, respiratory, and immune systems of the human body. Such particles are the most difficult to detect; therefore, their effects on human health have only been discovered in recent decades. Classical ultrasonic coagulation by sinusoidal action turns out to be ineffective for PM 2.5 due to the peculiarities of the physical mechanisms of hydrodynamic and orthokinetic interaction realized in gaseous media. This article presents a theoretical justification for choosing ways to increase the efficiency of ultrasonic coagulation of PM 2.5 by creating special conditions under which nonlinear disturbances of the velocity and pressure of the gas phase in the ultrasonic field occur. The authors performed simulations of ultrasonic coagulation under nonlinear disturbances of the velocity (vortex) and the pressure (shock waves), which has numerical difficulties due to the instability of existing methods. As a result of the numerical analysis, the possibility of increasing the coagulation rate of particles in the submicron size range up to limit values (13 times due to nonlinear pressure disturbances, and an additional increase of at least 2 times due to aerosol compaction in the vortex field of gas velocity) was shown.

The article presents the results of the development, optimization and research of the characteristics of an ultrasonic (US) emitter of increased power to create ultrasonic oscillatory systems designed to intensify processes in various industries. The increase in the power of the emitter was achieved by summing up the oscillations of low-power Langevin transducers on a diametrically oscillating summing overlay. In the process of research, the main problem of the proposed emitter was solved, which consists in the destruction of piezoceramic rings due to the presence of a high uneven distribution of the oscillation amplitudes of the piezoelectric packets. The decrease in unevenness is achieved by providing the optimal shape of the profile of the summing overlay. The manufactured emitter of ultrasonic vibrations has the following characteristics: resonant frequency – 30.05 kHz; acoustic power (continuous mode) – 1450 W; efficiency – 78%; oscillation amplitude – 26 µm.

The search for physical effects that contribute to the compaction of the cloud of aerosol particles is an urgent task. An analysis of nonlinear physical phenomena that occur during the formation of an acoustic field made it possible to establish that vortex acoustic flows turn out to be a significant factor in resonant oscillations of the gas gap, which, due to inertia forces, can cause local compaction of the aerosol cloud. A model similar to the discrete phase approach is proposed, which is capable of calculating the motion of an aerosol cloud. The possibility of a local increase in concentration by more than 2 times when exposed to a resonant air gap has been proven. It has been established that the maximum concentration of the aerosol cloud is achieved in areas with the maximum sound pressure level, which additionally contributes to an increase in the efficiency of coagulation. However, the maximum achievable degree of increase in concentration in the range of sound pressure levels from 150 to 155 dB decreases with increasing level. At the same time, with an increase in the level of sound pressure, the time to reach the maximum increase in concentration is reduced and, as is known, the efficiency of coagulation increases. This indicates the need to find the optimal sound pressure level for coagulation in the air gap.

Abstract A numerical model of ultrasonic coagulation of PM2.5 aerosol particles in three-dimensional vortex and turbulent acoustic flows is proposed in the article. The model is intended to identify the possibility of increasing the efficiency of the process. A numerical analysis of the model using the example of PM2.5 aerosol made it possible to establish that the presence of three-dimensional turbulent disturbances leads to the fact that the coagulation efficiency of PM2.5 reaches almost 100% at a sound pressure level of no more than 165 dB.

Separation of highly dispersed systems with huge liquid-gas or liquid-solid interfaces is relevant for practical tasks of gas purification from the most highly dispersed and difficult-to-detect dispersed fraction PM2.5, and separation of nanoparticles (including their small agglomerates) in fine chemical technology processes. One of the most effective ways to separate highly dispersed systems with a large interface surface is to combine each of the closed subsurfaces (surfaces of individual dispersed particles) under the influence of hydrodynamic effects in the gas phase, arising both near the interface surfaces and at a considerable distance from them, due to the superposition of ultrasonic vibrations. Since the efficiency of ultrasonic coagulation decreases with a large distance between closed subsurfaces from each other in PM2.5 aerosol and the small size of these surfaces, it is necessary to create conditions for the emergence of new nonlinear effects that contribute to the local compaction of the dispersed fraction. In a resonant and significantly inhomogeneous ultrasonic field (with a scale of inhomogeneity on the order of the wavelength), vortex acoustic flows arise, which, due to inertial forces, locally compact the dispersed phase in the form of an increase in the concentration of aerosol particles. A numerical model of ultrasonic coagulation of PM2.5 aerosol particles in three-dimensional (3D) vortex acoustic streaming is proposed in this paper. The model is designed to identify the possibility of increasing the efficiency of ultrasonic coagulation in 3D streaming by virtue of the following mechanisms: (1) local increase in concentration caused by the inertial transfer of particles to the periphery of 3D vortices in the gas phase; (2) increase in the frequency of particle collisions due to 3D turbulent disturbances in ultrasonic fields; and (3) increase in productivity and ensuring uninterrupted implementation of the process in a flow mode owing to transfer of particles between the streamlines of the main vortices initiated by ultrasonic vibrations. The listed mechanisms for increasing the efficiency of coagulation in 3D streaming are taken into consideration by introducing two stream functions, considering turbulent chaotic disturbances of the flow resulting in dispersion of particle velocities. It was possible to establish based on numerical analysis of the model using the example of PM2.5 that laminar vortex flows begin to influence at sound pressure level from 160-165 dB, and turbulent disturbances make an additional contribution in the range of sound pressure levels from 140-170 dB. At the same time, as a result of 3D turbulent disturbances, the efficiency of coagulation reaches almost 100% at a sound pressure level 5 dB lower than with laminar flows (sound pressure amplitude, 3 times lower).

The article is devoted to the study of the process of removing moisture from capillary-porous materials by its dispersion during the collapse of cylindrically-shaped cavitation bubbles formed in the capillaries of the material under ultrasonic exposure. A model has been proposed and developed that made it possible to explain the mechanism of dispersion during realization of the life cycle of a bubble in a capillary — slow growth, rapid expansion with deformation, and subsequent collapse. The range of sound pressure levels at which dispersion begins (from 150 dB) to the level at which bubbles reach the size of the capillary and the increase in the drying efficiency stops (170 dB) has been determined theoretically. It was also shown that for maximum efficiency in moisture removal, the size of the dehydrated sample must correspond to the ultrasonic wavelength in air. The mechanism of ultrasonic dispersion of liquid during drying has been confirmed experimentally and it has been established that to reduce the drying time by more than 40

The article presents the results of experimental studies of the process of ultrasonic drying of textile wool. It was found that additional ultrasonic exposure makes it possible to accelerate convective drying up to 7.5 times under constant initial experimental conditions. When cotton wool is exposed to ultrasound, thermal diffusion occurs. Water molecules move from the more heated center of the drying object to the less heated surface.

Relevance. The need for the development and widespread use of the ultrasonic spraying method, which has unique advantages, to solve the most pressing problems of modern industry. In particular: minimal, of all known methods, energy consumption for the implementation of the process, the possibility of forming fine droplets without the use of gas under pressure, regulating the dispersion of the formed aerosol by the parameters of the emitter, etc. However, for widespread practical use of the ultrasonic spraying method, it is necessary to ensure spraying conditions with a specified dispersion and productivity. In this regard, there is a need to develop a method for controlling and maintaining the necessary and sufficient thickness of the liquid layer on the surface of the piezoelectric transducer of the atomizer, the spraying of which will ensure, at a given spraying performance, the formation of an aerosol with the smallest deviation in the size of the formed droplets relative to the average value. It is proposed to control the thickness of the liquid layer by identifying the dependence of the resonant frequency of the piezoelectric transducer of the atomizer on the thickness of the liquid film on the oscillating surface of the atomizer. Aim. To develop a method and means for controlling the thickness of the layer of sprayed liquid by changing the resonant frequency of the ultrasonic oscillatory system and maintaining the optimal value of the layer thickness by changing the amplitude of vibrations of the surface of the ultrasonic sprayer. Objects. Liquid atomizing with ultrasonic high-amplitude vibrations. Methods. Obtaining the frequency characteristics of ultrasonic oscillatory systems, analyzing changes in the amplitude-frequency characteristics of oscillating systems and identifying criteria that allow monitoring and managing the ultrasonic spraying. Results. The authors have proposed and developed the method for indirectly monitoring the thickness of a sprayed liquid layer on the oscillating surface of an ultrasonic atomizer, based on measuring the resonant frequency of an ultrasonic oscillating system. The possibility of implementing the method and its practical application is caused by the fact that in the working range of layer thicknesses of the sprayed liquid, the change in the resonant frequency can reach 100 Hz, and with a frequency measurement accuracy of 1 Hz, the accuracy of determining the layer thickness will be no more than 2% of the working layer thickness. The identified dependencies and certain values of possible ranges of changes in the controlled parameter made it possible for the first time to develop a method for automatically controlling ultrasonic spraying, ensuring the maintenance of optimal modes of ultrasonic influence (amplitude of vibrations of the spray surface) and the thickness of the layer of sprayed liquid.

We propose a method for calculating the kinetics of ultrasonic coagulation of PM2.5 during fine gas cleaning that provides an order of magnitude higher calculation performance. Increased productivity is achieved through the proposed and justified method of reducing the original three-dimensional problem to a two-dimensional one. The proposed reduction method is based on the fact that the time of complete rotation of vortex acoustic flows turns out to be much shorter than the characteristic coagulation time during fine gas cleaning. This makes it possible to present the fractional composition of aerosol particles as a function of two stream functions instead of three coordinates. Calculations carried out using the proposed method make it possible to identify the possibility of increasing the efficiency of coagulation in three-dimensional flows due to the following mechanisms: a local increase in concentration caused by the inertial transfer of particles to the periphery of three-dimensional vortices in the gas phase, increasing the frequency of particle collisions due to three-dimensional turbulent disturbances in ultrasonic fields with a high amplitude of oscillatory velocity (more than 10 m/s), and increasing productivity and ensuring the possibility of continuous implementation of the process in flow mode due to the transfer of particles between the streamlines of the main vortices initiated by ultrasonic vibrations as well as due to external flows perpendicular to the plane of the vortices in three-dimensional space. The developed set of programs for implementing calculations can be used in the design of gas cleaning equipment.