STUDY OF CONVECTIVE FLOWS IN THREE-COMPONENT GAS MIXTURES BY THE METHOD OF NUMERICAL SIMULATION

2021 ◽  
Vol 73 (1) ◽  
pp. 103-109
Author(s):  
V.N. Kossov ◽  
◽  
V. Mukamedenkyzy ◽  
Z.Z. Yuldasheva ◽  
A. Khasseinova ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Average Velocity ◽  
Cylindrical Channel ◽  
Gas Mixtures ◽  
Physical Parameters ◽  
Loss Of Stability ◽  
Mechanical Equilibrium ◽  
Splitting Scheme ◽  
Heavy Component ◽  
Convective Flows

The characteristics of convective flows arising in three-component gas mixtures are investigated by the method of numerical simulation. The time variation of the isoconcentration lines of the heavy component of the mixture and the average velocity are considered as characteristics of convective flows. To calculate the characteristics of convective flows arising in a vertical cylindrical channel, we used a numerical model based on the splitting scheme according to physical parameters. It was shown that in three-component gas mixtures, where special diffusion regimes are manifested, non-monotonic distributions of component concentrations and velocities are possible. The time of loss of stability of mechanical equilibrium and the time of developed convective flows are determined.

scholarly journals ISOCONCENTRATION DISTRIBUTIONS OF COMPONENTS IN TERNARY GAS MIXTURES IN THE PRESENCE OF SPECIAL DIFFUSION MIXING MODES

2020 ◽  
Vol 69 (1) ◽  
pp. 230-236
Author(s):  
V.N. Kossov ◽  
◽  
V. Mukamedenkyzy ◽  
О.V. Fedorenko ◽  
М. Tuken ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Cylindrical Channel ◽  
Stability Loss ◽  
Gas Mixtures ◽  
Average Kinetic Energy ◽  
Physical Parameters ◽  
Splitting Scheme ◽  
Heavy Component ◽  
Convective Flows ◽  
Diffusion Mixing

The features of the formation of convective flows arising in three-component gas mixtures in the presence of special diffusion mixing regimes are investigated. The time variation of the isoconcentration lines of the heavy component of the mixture and the average kinetic energy are consideredas characteristics of convective flows. A numerical model based on the splitting scheme in physical parameters is used to calculate the characteristics of convective flows arising in a vertical cylindrical channel. It is shown that nonmonotonic distributions of component concentrations and kinetic energy can occur in ternary gas mixtures, where special diffusion regimes are manifested. The time of stability loss of the mechanical equilibrium of the mixture and the time of developed convective flows are determined.

HEXAGON-STRIPE TRANSITION AT THE MAGNETIC FIELD INDUCED PHASE TRANSFORMATIONS OF THE MAGNETORHEOLOGICAL SUSPENSIONS

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2345-2351 ◽  
Author(s):  
A. CEBERS
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Physical Parameters ◽  
Phase Boundaries ◽  
Modulated Phases ◽  
Magnetorheological Suspensions ◽  
Perturbed State ◽  
Magnetorheological Suspension ◽  
The Magnetic Field ◽  
Hele Shaw Cell

The phase diagram of the magnetorheological suspension allowing for the modulated phases in the Hele-Shaw cell under the action of the normal field is calculated. The phase boundaries between the stripe, the hexagonal and the unmodulated phases in dependence on the layer thickness and the magnetic field strength are found. The existence of the transitions between the stripe and the hexagonal phases at the corresponding variation of the physical parameters is illustrated by the numerical simulation of the concentration dynamics in the Hele-Shaw cell. It is remarked that those transitions in the case of the magnetorheological suspensions can be caused by the compression or the expansion of the layer. Among the features noticed at the numerical simulation of the concentration dynamics in the Hele-Shaw cell are: the stripe patterns formed from the preexisting hexagonal structures are more ordered than arising from the initial randomly perturbed state; at the slightly perturbed boundary between the concentrated and diluted phases the hexagonal and the inverted hexagonal phases are formed and others.

Calculation and Design Method Study of the Coil-Wound Heat Exchanger

2014 ◽  
Vol 1008-1009 ◽  
pp. 850-860 ◽  
Author(s):  
Zhou Wei Zhang ◽  
Jia Xing Xue ◽  
Ya Hong Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Exchanger ◽  
Design Method ◽  
Fluid Velocity ◽  
Exchange Process ◽  
Three Dimensional ◽  
Simulation Method ◽  
Physical Parameters ◽  
Numerical Result

A calculation method for counter-current type coil-wound heat exchanger is presented for heat exchange process. The numerical simulation method is applied to determine the basic physical parameters of wound bundles. By controlling the inlet fluid velocity varying in coil-wound heat exchanger to program and calculate the iterative process. The calculation data is analyzed by comparison of numerical result and the unit three dimensional pipe bundle model was built. Studies show that the introduction of numerical simulation can simplify the pipe winding process and accelerate the calculation and design of overall configuration in coil-wound heat exchanger. This method can be applied to the physical modeling and heat transfer calculation of pipe bundles in coil wound heat exchanger, program to calculate the complex heat transfer changing with velocity and other parameters, and optimize the overall design and calculation of spiral bundles.

Numerical simulation of seismic waves in porous media components

2021 ◽  
Vol 9 (1) ◽  
pp. 4-30
Author(s):  
M. Azeredo ◽  
◽  
V. Priimenko ◽  
Keyword(s):  
Numerical Simulation ◽  
Porous Medium ◽  
High Frequency ◽  
Seismic Waves ◽  
Computational Algorithm ◽  
Low Frequency ◽  
Physical Parameters ◽  
Mathematical Algorithm ◽  
Biot Equations ◽  
Attenuation And Dispersion

This work presents a mathematical algorithm for modeling the propagation of poroelastic waves. We have shown how the classical Biot equations can be put into Ursin’s form in a plane-layered 3D porous medium. Using this form, we have derived explicit for- mulas that can be used as the basis of an efficient computational algorithm. To validate the algorithm, numerical simulations were performed using both the poroelastic and equivalent elastic models. The results obtained confirmed the proposed algorithm’s reliability, identify- ing the main wave events in both low-frequency and high-frequency regimes in the reservoir and laboratory scales, respectively. We have also illustrated the influence of some physical parameters on the attenuation and dispersion of the slow wave.

scholarly journals Numerical study of gas dynamics and heat transfer in matrix channels at various rib angles

2021 ◽  
Vol 2057 (1) ◽  
pp. 012026
Author(s):  
A V Barsukov ◽  
V V Terekhov ◽  
V I Terekhov
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Reynolds Number ◽  
Gas Dynamics ◽  
Average Velocity ◽  
Numerical Study ◽  
Reynolds Numbers ◽  
Separation Flow ◽  
Maximum Heat ◽  
Maximum Heat Transfer

Abstract The results of numerical simulation of the separation flow in matrix channels by the RANS method are presented. The simulation is performed at the Reynolds number Re = 12600, determined by the mass-average velocity and the height of the channel. The distribution of the local Nusselt number is obtained for various Reynolds numbers in the range of 5÷15⋅103 and several rib angles. It is shown that the temperature distribution on the surface is highly nonuniform; in particular, the maximum heat transfer value is observed near the upper edge facets, in the vicinity of which the greatest velocity gradient is observed.

Dynamics of Shock Waves in the Cylindrical Channel With Confusers

2009 ◽  
Vol 4 (2) ◽  
pp. 13-18
Author(s):  
Igor Anufriev ◽  
Aleksandr Golovanov ◽  
Aleksandr Tsimbalyuk ◽  
Oleg Sharypov
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Shock Wave ◽  
Shock Wave Front ◽  
Gas Flow ◽  
Cylindrical Channel ◽  
Maximal Pressure ◽  
The Mathematical Model ◽  
Forest Combustible ◽  
Gunpowder Charge

Current work covers experimental and theoretical investigation of conic confusers impact on the intensity shock wave, generated in the shock tube by explosion of gunpowder charge. For given conditions optimal geometric characteristics of the confuser, providing maximal pressure in the shock wave front, were found experimentally. The mathematical model was developed and numerical simulation of the axisymmetric shock-wave gas flow in the channel was carried out. Experimentally was shown, that the application of the optimal confuser provides significant increase of the efficiency gasdynamic effect on the combustion of forest combustible materials.

Investigation of the Submerged Depth of Aeration Impellers in an Oxidation Ditch by Numerical Simulation

2012 ◽  
Vol 178-181 ◽  
pp. 429-432
Author(s):  
Y. L. Liu ◽  
B. Lv ◽  
W.L. Wei
Keyword(s):  
Numerical Simulation ◽  
Velocity Distribution ◽  
Average Velocity ◽  
Sewage Treatment ◽  
Processing System ◽  
Simulation Method ◽  
Velocity Fields ◽  
Oxidation Ditch ◽  
Depth Direction ◽  
Sewage Treatment System

In this paper, the flow structure of the oxidation ditch was studied using numerical simulation method and different submerged depth of aeration impellers. The computed velocity fields were analyzed, which shows that under the same conditions, and by using the optimal submerged depth the average velocity of the flow in oxidation ditch is increased and the velocity near-bottom has increased significantly. The results of comparisons show that the velocity distribution is more uniform along the depth direction, and that the flow velocity distribution structure can prevent sludge from settling in the oxidation ditch processing system at the submergence ratio called the optimal submergence ratio, which helps to improve the efficiency of oxidation ditch sewage treatment system.

scholarly journals Parallel Numerical Simulation of the Magnetic Moment Reversal within the φ0-Josephson Junction Spintronic Model

2020 ◽  
Vol 226 ◽  
pp. 02018
Author(s):  
Stefani Panayotova ◽  
Maxim Bashashin ◽  
Elena Zemlyanaya ◽  
Pavlina Atanasova ◽  
Yury Shukrinov ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Magnetic Moment ◽  
Information Technologies ◽  
Parallel Implementation ◽  
Numerical Study ◽  
Nonlinear Differential Equations ◽  
Computer Code ◽  
Computer Time ◽  
Physical Parameters ◽  
Wide Range

The φ0-Josephson Dushanbe, Tajikistanjunction model with a coupling between the magnetic moment and the Josephson current in the “superconductor–ferromagnet–superconductor” system has been investigated. Numerical solution of the respective system of nonlinear differential equations is based on the two-stage Gauss–Legendre algorithm. For numerical simulation in a wide range of parameters which requires a significant computer time, a parallel MPI=C++ computer code has been developed. Results of numerical study of the magnetization effect depending on physical parameters, as well as results of methodological calculations demonstrating the efficiency of the parallel implementation, are presented. Calculations have been carried out at the Heterogeneous Platform “HybriLIT” and on the supercomputer “Govorun” of the Multifunctional Information and Computing Complex of the Laboratory of Information Technologies, JINR (Dubna).

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