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Journal of Applied Mechanics and Technical Physics

2022 year, number 5

Numerical Simulation of Enrichment of the Air-Helium Mixture with a Bifunctional Sorbent Based on Glass Microspheres

A. S. Vereshchagin1,2,3, I. V. Kazanin1,2, V. N. Zinoviev1, V. M. Fomin1,2
1Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
2Novosibirsk State University, Novosibirsk, 630090, Russia
3Novosibirsk State Technical University, Novosibirsk, 630073, Russia
Keywords: composite sorbent, helium, microspheres, membrane-sorption method, numerical simulation, short-cycle adsorption, hyperbolic model

Abstract >>
A hyperbolic character of the convective part of the flow of an air-helium mixture through a granulated sorbent layer with allowance for the Forchheimer filtration is demonstrated. A numerical model of a one-dimensional flow of the air-helium mixture through an adsorber filled by a granulated sorbent with due allowance for air and helium diffusion inward cylindrical granules and helium confinement in microspheres. Within the framework of this model, verification of a numerical algorithm in problems of gas filtration through a porous medium and propagation of a pressure wave formed by the incident shock wave over a gas medium is performed. Experimental and numerical data are obtained and are found to be in good agreement. The enrichment phase is modeled by the method of short-cycle adsorption with the use of a bifunctional sorbent based on microspheres. It is demonstrated that the mass fraction of helium in the air-helium mixture can be almost doubled (from 0.7 to 1.3%)with the helium extraction degreeof 9 0.4%.

DC Discharge between Metal Anode and Liquid Non-Metallic Cathode

S. Yu. Petryakov1, D. N. Mirkhanov1, A. F. Gaisin2, R. Sh. Basyrov1, N. F. Kashapov3
1Kazan National Research Technical University named after A. N. Tupolev, Kazan, 420111 Russia
2Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow, 125412 Russia
3Kazan Federal University, Kazan, 420008 Russia
Keywords: low-temperature plasma, electric discharge, plasma-liquid systems, numerical methods

Abstract >>
The characteristics and mathematical modeling of the behavior of a low-temperature direct current electric discharge plasma ignited between an aluminum anode and an electrolytic cathode (3% NaCl solution in purified water) at atmospheric pressure have been studied. The discharge is ignited by immersing the metal anode into the electrolytic cathode. The types and forms of plasma structures generated in the interelectrode gap are considered. The results of high-speed recording of the processes of breakdown and combustion of the discharge are presented. The electrophysical parameters of the discharge, including pulsations, current and voltage fluctuations, have been studied. The emission spectroscopy method was used to determine the discharge radiation spectrum, plasma composition, electron concentration, and temperature of heavy plasma components. The thermograms of the surface of liquid non-metallic and metallic electrodes in the discharge burning zone are considered. The results of numerical simulation of the electric field strength and the initial stage of the discharge are presented.

High-Temperature Annealing of Thin Silicon Suboxide Films Produced by the Method of Gas-Jet Chemical Deposition with Activation by Electron-Beam Plasma

E. A. Baranov1, A. O. Zamchii1,2, N. A. Lunev1,2, I. E. Merkulova1, V. A. Volodin3,4, M. R. Sharafutdinov5, A. A. Shapovalova6
1Kutateladze Institute of Thermal Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
2Novosibirsk State University
3Novosibirsk State University, Novosibirsk, 630090, Russia
4Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
5Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
6Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
Keywords: nanocrystalline silicon, nonstoichiometric silicon oxide, thin film synthesis

Abstract >>
Thin films of amorphous nonstoichiometric silicon oxide (a-SiOx:H, 0 < x < 2) have been synthesized by gas-jet deposition with activation by an electron-beam plasma. The stoichiometric coefficient of the a-SiOx:H films was varied in the range 0.47-1.63 depending on the parameter R determined by the mixture flow rate Ar-SiH4. High-temperature (at a temperature of 950°C for 2 h) annealing of a-SiOx:H thin films led to the formation of 8.3-12.3 nm crystalline silicon nanoparticles. It is shown that with an increase in the parameter R, the degree of crystallinity of the annealed films increases up to 66%. It has been suggested that the position of the peak of nanocrystalline silicon in the Raman spectra is affected by mechanical stresses. As a result of a quantitative assessment of such a stress, the values of 1.0-1.7 GPa are obtained.

Protective Performance of a Three-Layer Explosive Welded Plate Impacted by Spherical Fragments at Different Incident Angles

N. Zhou1,2,3, D. Liu1, Q. Nian4, K. Tang1, J. Wang1, Yu. Fang3
1Nanjing University of Science and Technology, Nanjing 210094, Jiangsu, China
2Nanjing Forest Police College, Nanjing 210023, Jiangsu, China
3Anhui Honlly Clad Metal Materials Technology Co., Ltd, Xuancheng 242000, Anhui, China
4China Railway Ten Bureau Group Third Construction Co. Ltd, Hefei 230601, Anhui, China
Keywords: impact dynamics, welding, plate, incident angle, protective performance, failure mode

Abstract >>
The protective performance of a three-layer explosive welded composite plate consisting of steel and aluminum plates is studied in ballistic experiments and numerical simulations. The mechanism of target plate failure under the impact of spherical fragments is investigated.

Variational Problems for Some Equations of the Combustion Theory

I. G. Donskoi
Melentiev Energy Systems Institute, Siberian Branch, Russian Academy of Sciences, Irkutsk, 664033, Russia
Keywords: variational methods, equations of reaction-diffusion-convection, thermal explosion, reaction waves

Abstract >>
Variational formulations are proposed for the equations describing the stationary states of nonisothermal one-dimensional reactors, including those under convective transfer. For the proposed variational formulations, several variants of the numerical solution are considered (based on the method of local variations and the Rayleigh-Ritz method). The features of the use of numerical methods in solving the considered problems are discussed: convergence, the ratio of the spatial grid step to the degree of the approximating polynomial. Modifications of the problem of thermal ignition are considered taking into account convective transfer and heat losses. A variational principle is proposed that determines the structure of the combustion front at a given propagation velocity. It is shown that this variational principle can be used along with the principle of minimum entropy production for a complete solution of the problem of stationary propagation of an exothermic reaction wave.

Synthesis on the Existence/Non-Existence of Multiple Solutions for an Unsteady Non-Rotating Shrinking Disk Flow

A. Mehmood1, G. D. Tabassum1, M. Usman2, A. Dar3
1International Islamic University, Islamabad, 44000, Pakistan
2Virtual University of Pakistan, Lahore, Pakistan
3University of Kotli, Kotli, Azad Jammu and Kashmir, Pakistan
Keywords: Shrinking disk, unsteady flow, non-uniqueness, numerical solution

Abstract >>
Results of studying the problem of an unsteady fluid flow along an instantaneously stretching (shrinking) non-rotating disk with an infinite radius are reported. The velocity of the shrinking disk surface is chosen in such a way that the problem allows the existence of an exact similarity solution. The original problem is reduced to an initial-value problem, which is solved numerically by using the shooting and Newton-Raphson methods. A detailed study of the existence and uniqueness of the solution is performed.

Axisymmetric Motion of an Incompressible Couple Stress Fluid between Two Eccentric Rotating Spheres

A. Al-Hanaya1, Shreen El-Sapa2, E. A. Ashmawy2
1Princess Nourah bint Abdulrahman University, Riyadh, 11671, Saudi Arabia
2Alexandria University, Alexandria, Egypt
Keywords: couple stress fluids, rotational motion, eccentric spheres, torque, collocation method

Abstract >>
This study deals with axisymmetric steady rotational movement of an incompressible couple stress fluid between two non-concentric objects. Two spherical boundaries are revolving axially with different angular velocities. At low Reynolds numbers, the solution is obtained semi-analytically utilizing the superposition guideline and the collocation approach. The hydrodynamic couple exerted by the fluid on the internal particle is considered. The results obtained in the study are compared with the corresponding results of the classical viscous fluids available in the literature.

Asymmetry of the Flight of Flat Liners Accelerated by a Magnetic Field

A. A. Bazanov1, B. E. Grinevich1, A. B. Ivanovskii1,2
1All-Russian Research Institute of Experimental Physics, Sarov, 607188, Russia
2Sarov Institute of Physics and Technology, Sarov, 607189, Russia
Keywords: capacitor unit, shock and shockless compression of materials, discharge current, liner velocity, electrocontact measurement technique, liner flight base

Abstract >>
Experiments on acceleration of flat metal liners by a magnetic field were performed on the Kaskad capacitor facility. Data on the asymmetry of the flight of liners both along the streamline and in the transverse direction are presented.

Hydrodynamic Loads during Acceleration of a Cylinder under a Free Surface

A. E. Golikov, N. I. Makarenko
Lavrent'ev Institute of Hydrodynamics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
Keywords: free boundary, circular cylinder, hydrodynamic loads

Abstract >>
The accelerated motion of a circular cylinder from the state of rest under the free surface of an infinitely deep ideal fluid is studied using the method of reducing the original mathematical formulation of the problem to an integrodifferential system of equations for the function specifying the free surface shape and for the normal and tangential velocity components on the free surface. An analytic continuation of the velocity field into the flow region is constructed and unsteady loads acting on the cylinder at the initial stage of motion are determined.

Investigation of an Oscillatory Multiphase Flow in a Double Porosity Medium with a Chemically Active Skeleton

S. M. Bazov1, I. N. Zavialov1, A. V. Konyukhov1,2
1Moscow Institute of Physics and Technology, Dolgoprudny, 141700, Russia
2Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow, 125412, Russia
Keywords: self-oscillating mode, porosity medium, acidizing, double porosity, numerical investigation

Abstract >>
The transition of a filtration reactive flow in a double porosity medium into a self-oscillating mode is studied. Flow stability is analyzed using numerical methods for solving multiphase filtration equations in a medium with double porosity. The region of development of self-oscillations is investigated depending on the external parameters of the system and the properties of the reagents.

Local Equilibrium Approximation in the Mathematical Model of the Far Turbulent Wake Behind a Body of Revolution

V. N. Grebenev1, A. G. Demenkov2,3, G. G. Chernykh1
1Federal Research Center for Information and Computational Technologies, Novosibirsk, 630090, Russia
2Kutateladze Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
3Novosibirsk State Technical University, Novosibirsk, 630073, Russia
Keywords: method of differential constraints, three-parameter model of the turbulent wake, local equilibrium approximation, turbulent wake behind the body of revolution, numerical simulation

Abstract >>
The flow in the far turbulent wake behind a body of revolution is studied with the use of a three-parameter turbulence model, which includes differential equations of the turbulent energy balance, transport equation for the turbulent energy dissipation rate, and turbulent shear stress equation. Local equilibrium algebraic truncation of the transport equation for the turbulent shear stress yields the known Kolmogorov-Prandtl equation. Under a certain constraint on the values of the empirical constants and for the law of time scale growth consistent with the mathematical model, this equation is a differential constraint of the model or an invariant manifold in the phase space of the corresponding dynamic system. The equivalence of the local equilibrium approximation and the condition of the zero value of the Poisson bracket for the normalized turbulent diffusion coefficient and defect of the longitudinal component of velocity is demonstrated. Results of numerical experiments are reported; they are found to be in good agreement with theoretical predictions.

Aerodynamic Features of a Rotating Cylinder with a Deflector

A. R. Bakhtybekova1, N. K. Tanasheva1, L. L. Minkov2, N. N. Shuyushbaeva3, A. N. Dyusembaeva1
1Buketov Karaganda University, Karaganda, 100026, Kazakhstan
2National Research Tomsk State University, Tomsk, 634050, Russia
3Ualikhanov Kokshetau University, Kokshetau, 020000, Kazakhstan
Keywords: wind turbine, deflector, cylinder, Magnus effect, modeling

Abstract >>
Numerical and experimental methods are used to investigate the aerodynamic characteristics of a laboratory sample in the form of a cylinder with an active rotating element - a deflector-that can be used as a working power blade element of awind power plant. Numerical simulation was performed using the Ansys Fluent software based on the Reynolds-averaged Navier-Stokes equations supplemented by a realizable (κ-ε)-turbulence model. Based on the results of numerical simulation, a laboratory model with a cylinder 205 mm long and 50 mm in diameter and a deflector 100 mm in diameter was made for experimental studies. A comparative analysis of the numerical and experimental aerodynamic characteristics of the model was carried out and the aerodynamic features of the airflow around the test sample were identified.

On the Theory of Slope Flows over a Thermally Inhomogeneous Surface

L. Kh. Ingel'1,2
1Research and Production Association "Taifun", Obninsk, 249038 Russia
2A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, Moscow, 119017, Russia
Keywords: slope currents, thermal inhomogeneities, density currents, linear perturbations, analytical model

Abstract >>
A two-dimensional stationary linear model of flows arising in a stably (neutral) stratified medium over a thermally inhomogeneous flat inclined surface is analyzed analytically. At the lower boundary, temperature deviations are specified, which depend harmonically on the horizontal coordinate transverse to the slope. Explicit analytical solutions are obtained, which make it possible to analyze the regularities of emerging density flows. It is shown that these flows can qualitatively differ depending on the ratio of the slope angle of the lower boundary and the analog of the Rayleigh number, the expression for which includes the horizontal scale of the thermal inhomogeneity region as a spatial scale. An appropriate criterion for distinguishing these currents is established.

Reflection and Refraction of Sound Waves at the Interface between a Bubbly Liquid and a Porous Medium Saturated with a Bubbly Liquid

L. F. Sitdikova, I. K. Gimaltdinov
Ufa State Oil Technical University, Ufa, 450064, Russia
Keywords: sound wave, porous medium, reflection coefficient, transmission coefficient

Abstract >>
The reflection and transmission of harmonic waves is theoretically investigated at the interface between a bubbly liquid and a porous medium saturated with this liquid has been studied theoretically. The influence of the parameters of the system on the coefficients of reflection and transmission through the interface between the two media has been investigated. It has been found that for the interface between the bubbly liquid and the porous medium saturated with the bubbly liquid, there is a range of frequencies in which reflection occurs in the same way as from a free surface and the back reflection as from a rigid wall.

Delamination of Multilayered Inhomogeneous Beams under Nonlinear Creep

V. Rizov1, H. Altenbach2
1University of Architecture, Civil Engineering and Geodesy, Sofia, 1046, Bulgaria
2Otto-von-Guericke-Universitat Magdeburg, Magdeburg, 39106, Deutschland
Keywords: multilayered beam, inhomogeneous material, nonlinear creep, delamination

Abstract >>
This paper is focused on deriving a common solution to the strain energy release rate for delamination cracks in multilayered inhomogeneous beams under nonlinear creep. The layers of the beams exhibit material inhomogeneity in the thickness direction. The solution is obtained for the nonlinear stress-strain-time relation. The J -integral approach is applied to verify the solution. The variation of the strain energy release rate with time as a result of the nonlinear creep behaviour is analyzed.

Plate Flutter Problem with Mixed Boundary Conditions

S. D. Algazin1, I. A. Selivanov2
1Ishlinsky Institute for Problems in Mechanics, Russian Academy of Sciences, Moscow, 119526, Russia
2Lomonosov Moscow State University, Moscow, 119991, Russia
Keywords: numerical methods without saturation, plate flutter, flutter critical velocity, analytical dependence

Abstract >>
The paper considers the solution of the plate flutter problem with mixed boundary conditions. The mathematical formulation of the problem allows taking into account arbitrary directions of the incoming flow vector. For the numerical solution of the problem, a modern numerical algorithm without saturation is proposed, which allows obtaining the critical flutter speed with sufficient accuracy on a sparse grid. The results of calculations for four materials are presented: titanium, steel, aluminum, duralumin. Based on the calculation results, two analytical dependences for the critical flutter speed are obtained: from the direction of the incoming flow vector, as well as from the dimensionless speed of sound in the plate and the thickness of the plate. The eigenforms Re(φ) corresponding to the critical flutter speed are given.

Cracks in Hybrid Fiber Metal-Laminated Nanocomposites under Uniaxial Tension

M. Babanly, R. Mekhtiyev, N. Gurbanov, D. Aslanov, Yu. Tanriverdiev
Azerbaijan State University of Oil and Industry, Baku, AZ1010, Azerbaijan
Keywords: elliptical crack, hybrid nanocomposite, tension, plasticity

Abstract >>
A technology for obtaining hybrid nanocomposite materials with a 7075-T6 aluminum matrix and a filler in the form nanoparticles is proposed. A review of experimental data and computer and theoretical models of crack initiation processes is presented. The mechanisms of microcrack nucleation under uniaxial tensile load are determined. To study the fracture of loaded nanocrystalline materials and determine their mechanisms, a model is proposed that describes the formation and growth of nanocracks near the tips of elliptical cracks in a hybrid nanocomposite material. The dependences between the applied force and the crack length are obtained using the parameters of a modeled crack.

Viscoelastic Properties of Silicone Rubber with Addition of Carbon Nanotubes

V. M. Kulik
Kutateladze Institute of Thermal Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
Keywords: silicone rubber, single-walled carbon nanotubes, elastic modulus, loss factor

Abstract >>
A study was made of the change in the dynamic viscoelastic properties of silicone rubber with the addition of a small fraction (0.05; 0.10%) of single-walled carbon nanotubes. In the region of linear deformation, the elastic modulus and loss factor were measured. It has been established that the addition of nanotubes and the aging of materials lead to an increase in the elastic modulus, and the loss factor can either increase or decrease.

Rod Torsion in Kinematic Creep Regimes

I. A. Bashchikova
Lavrentyev Institute of Hydrodynamics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
Keywords: torsion, rod, deformation of the cross section, kinematic modes, creep, inverse problem

Abstract >>
Problems are considered that describe the process of obtaining the residual angle of twist of a rod under creep conditions, taking into account elastic recovery after unloading. It is assumed that a constant linear angle of twist is set for the section being formed, i.e., the section is in conditions of pure torsion, without constraining the ends of the rod. It is believed that strains and stresses depend only on time and two spatial coordinates in the plane of the cross section of the rod. Direct and inverse problems of torsion of a rod with rectangular and angular cross sections in various kinematic creep regimes are considered. The speed of the angle of twist during the entire deformation process is set constant. A method of numerical calculation based on the finite element method is proposed, which makes it possible to obtain the stiffness characteristics of the section under torsion in the case of creep. It is shown that the minimum level of residual stresses is observed in the relaxation mode of deformation. For a rod with a cross-section of the angular type, modes are found in which stresses significantly decrease in the area of their concentration.

Experimental Study and Visualization of the Particle-Bubble Collision Process

M. Mohammadi1, M. Nazari1, M. H. Kayhani1, G. Ahmadi2
1Shahrood University of Technology, Shahrood, Iran
2Clarkson University, Potsdam, NY 13699-5725, USA
Keywords: Particle-bubble collision, sliding velocity, modified Bond number, three-phase contact line

Abstract >>
In the present study, an experimental approach is developed to study collisions of particles with a fixed air bubble. An air bubble with a diameter of 5.5 mm in deionized water is created, plastic particles (with diameters of 1.5, 2, and 2.5 mm) are released at different heights from the bubble surface, and their collisions with the bubble surface are studied. The results show that the particle size significantly affects the particle velocity and sliding time on the bubble surface. As the particle diameter increases, its sliding velocity on the bubble surface increases, and the particles are detached quickly from the bubble surface. The effects of the drag, capillary, pressure, weight, and buoyancy forces acting on the particles during the attachment-detachment on the bubble surface are also studied. The results show that the particle stays attached if the capillary force is dominant. The effects of the three-phase contact line on the capillary and pressure forces are also analyzed. A modified Bond number is proposed to check the attachment-detachment regimes.