Mathematical Modeling of Gas-Solid Two-Phase Flows: Problems, Achievements and Perspectives (A Review)

Varaksin, A. Yu.; Ryzhkov, Sergei V.

doi:10.3390/math11153290

Cited by 7 publications

(3 citation statements)

References 119 publications

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“…The size of particles with nanometer range and their high resistance to agglomeration and sedimentation allowed to gain very stable aqueous suspensions of nanoparticles without the application of any surface-active stabilizing agents. It is necessary to note, that a range of technical solutions for similar kinds of discharges was recently proposed by Kusenov and Ryzhkov with coworkers [7][8][9][10][11][12][13][14][15][16]. In these studies, discharges of various configurations, also taking into account electric and magnetic fields, as well as different mechanisms of influence on the objects, were applied in plasma experiments.…”

Section: Methodsmentioning

confidence: 99%

Mechanical properties of polymer composite films with ZnO nanoparticles synthesized in low-temperature plasma under ultrasonic cavitation

Butusova,

Filatov,

Bulychev

2024

J. Phys.: Conf. Ser.

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In this study, polymer nanocomposite materials consisting of the copolymer of ethylene and vinyl acetate as a matrix and nanoparticles of zinc oxide as a filler have been obtained and examined by physicochemical and mechanical methods. Zinc oxide nanoparticles used in this study were fabricated using the plasma discharge under the effect of intensive ultrasonic cavitation. To ensure that resulting nanocomposites will acquire homogeneous distribution of filler nanoparticles, solution technology was utilized followed by the melt compounding technique, and also nanoparticles treated and non-treated with ultrasound were applied. The fabricated samples of nanocomposite material films were examined by X-ray phase analysis, then X-ray fluorescence analysis as well as scanning electron microscopy. The differences between the samples were demonstrated: when the nanoparticles without ultrasonic treatment were used, the particles were found to be more strongly aggregated within the bulk of the composite material and the average size of particles was visually larger in comparison to the sample filled with nanoparticles subjected to ultrasonic action. Finally, studies of the tensile strength and relative deformation of the samples were carried out. From the results of mechanical tests, it can be seen that, according to both studied parameters, there is an optimal concentration of ZnO nanoparticles. For tensile strength, the highest result was obtained at a concentration of nanoparticles of 3%, and for the relative elongation to rupture of the sample, the highest value was achieved at a concentration of nanoparticles of 2%.

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Section: Methodsmentioning

confidence: 99%

Mechanical properties of polymer composite films with ZnO nanoparticles synthesized in low-temperature plasma under ultrasonic cavitation

Butusova,

Filatov,

Bulychev

2024

J. Phys.: Conf. Ser.

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“…The downdraft mechanism and in-and-up mechanism are needed to start the process In conclusion, we mention works [119,146,147] in which the authors tried to take into account the influence of both mechanisms (downdraft mechanism and in-and-up mechanism) on tornado generation and dynamics in their calculations.…”

Section: Main Factors Of Tornadogenesismentioning

confidence: 99%

Mathematical Modeling of Structure and Dynamics of Concentrated Tornado-like Vortices: A Review

Varaksin

Ryzhkov

2023

Mathematics

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Mathematical modeling is the most important tool for constructing the theory of concentrated tornado-like vortices. A review and analysis of computational and theoretical works devoted to the study of the generation and dynamics of air tornado-like vortices has been conducted. Models with various levels of complexity are considered: a simple analytical model based on the Bernoulli equation, an analytical model based on the vorticity equation, a new class of analytical solutions of the Navier–Stokes equations for a wide class of vortex flows, and thermodynamic models. The approaches developed to date for the numerical simulation of tornado-like vortices are described and analyzed. Considerable attention is paid to developed approaches that take into account the two-phase nature of tornadoes. The final part is devoted to the analysis of modern ideas about the tornado, concerning its structure and dynamics (up to the breakup) and the conditions for its occurrence (tornadogenesis). Mathematical modeling data are necessary for interpreting the available field measurements while also serving as the basis for planning the physical modeling of tornado-like vortices in the laboratory.

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“…The results showed that the particles had a small diameter and showed hysteresis effects in the reaction zone. Varaksin et al [13] performed multiphase flow simulations with differently sized particles (polydisperse particles) and concluded that differently sized particles produce different velocities, affect the gas flow differently, and tend to collide with each other at lower concentrations. Yue et al [14] used the CFD-DEM method to study the effect of the particle density on nozzle deflection under three conditions of constant fluidization velocity, amplified fluidization velocity, and particle density.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation and Experimental Study of Gas–Solid Two-Phase Spraying of Dry Powder Fire-Extinguishing System Based on Fire-Extinguishing Inspection Robot

Chu,

Chen,

Gan

et al. 2024

Processes

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In order to solve the problem where the traditional intelligent inspection robot only has a single inspection function, we studied the use of a dry powder (including an ultra-fine dry powder) as a fire-extinguishing medium for the first time. In fire-extinguishing robots, the spray pressure is difficult to control, and there are several other issues. For integrated inspection, an intelligent, nitrogen-driven fire-extinguishing robot using a dry powder in a pressure-controlled spray was developed. On this basis, in order to investigate nitrogen-driven dry powder particle spraying as a gas–solid two-phase mechanism, as well as the flow characteristics and the influence of relevant parameters on the spraying effect, a nitrogen-driven dry powder particle spraying system was established as part of a gas–solid two-phase computational fluid dynamics model. The flow field of the spraying system and the particle motion characteristics were analyzed to explore the micro-mechanisms of the influence of different driving pressures, pipe diameters, and nozzle configurations on the spraying of the dry powder. In order to investigate the macroscopic effect of dry powder spraying where the gas–solid two-phase micro-mechanisms could not be revealed, an experimental platform was set up, and the experiments verified the accuracy of the numerical simulation results. We also investigated the dry powder spraying effect under different driving pressures, pipe diameters, nozzle configurations, and loading ratios. Finally, an orthogonal test was designed based on the results of the single-factor experiments to find the best combination of parameters required to achieve the optimal spraying effect. The research results can provide a theoretical and technical reference for the design and development of nitrogen-driven dry powder spraying systems.

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Mathematical Modeling of Gas-Solid Two-Phase Flows: Problems, Achievements and Perspectives (A Review)

Cited by 7 publications

References 119 publications

Mechanical properties of polymer composite films with ZnO nanoparticles synthesized in low-temperature plasma under ultrasonic cavitation

Mechanical properties of polymer composite films with ZnO nanoparticles synthesized in low-temperature plasma under ultrasonic cavitation

Mathematical Modeling of Structure and Dynamics of Concentrated Tornado-like Vortices: A Review

Numerical Simulation and Experimental Study of Gas–Solid Two-Phase Spraying of Dry Powder Fire-Extinguishing System Based on Fire-Extinguishing Inspection Robot

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