scholarly journals About realization of one-dimensional quasi-gas dynamic algorithm in the open program OpenFOAM complex

2018 ◽  
pp. 1-19 ◽  
Author(s):  
Maria Alexandrovna Istomina
Keyword(s):  
Dynamic Algorithm ◽  
One Dimensional ◽  
Gas Dynamic ◽  
Open Program

scholarly journals Dissipation of turbulence by magnetohydrodynamic shock waves

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
Andrew Lehmann ◽  
Mark Wardle
Keyword(s):  
Shock Front ◽  
Fluid Model ◽  
Neutral Species ◽  
One Dimensional ◽  
Neutral Gas ◽  
Gas Dynamic ◽  
Magnetohydrodynamic Shock ◽  
Two Fluid Model ◽  
Ion Species ◽  
Two Fluid

AbstractWe characterise steady, one-dimensional fast and slow magnetohydrodynamic (MHD) shocks using a two-fluid model. Fast MHD shocks are magnetically driven, forcing ions to stream through the neutral gas ahead of the shock front. This magnetic precursor heats the gas sufficiently to create a large, warm transition zone where all fluid variables only weakly change in the shock front. In contrast, slow MHD shocks are driven by gas pressure where neutral species collide with ion species in a thin hot slab that closely resembles an ordinary gas dynamic shock.We computed observational diagnostics for fast and slow shocks at velocities vs=2–4 km/s and preshock Hydrogen nuclei densities nH = 102-4 cm−3. We followed the abundances of molecules relevant for a simple oxygen chemistry and include cooling by CO, H2 and H2O. Estimates of intensities of 12CO rotational lines show that high-J lines, above J = 6 → 5, are more strongly excited in slow MHD shocks.

scholarly journals Supercomputer model of dynamical dusty gas with intense momentum transfer between phases based on OpenFPM library

2021 ◽  
Vol 2099 (1) ◽  
pp. 012056
Author(s):  
Vitaliy Grigoryev ◽  
Olga Stoyanovskaya ◽  
Nikolay Snytnikov
Keyword(s):  
Continuous Medium ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Point Explosion ◽  
Vector Data ◽  
Sph Method ◽  
One Dimensional ◽  
Gas Dynamic ◽  
Plane Sound ◽  
Gas Dynamic Equations

Abstract The paper considers the solution of model gas-dynamic problems (propagation of plane sound wave, one-dimensional shock tube problem, three-dimensional problem of a point explosion in a continuous medium) in the case of a gas-dust medium. The interaction of dust and gas was taken into account using the IDIC method within the SPH method used to solve gas-dynamic equations. An important feature of the work is the use of the open computational package OpenFPM, which makes it easy to carry out parallel computations. The main advantage of this package is the ready-made (implemented by the authors of the package) and intuitive, automatically parallelizable vector data structures, the use of which is identical both in the case of calculations on a personal computer and in the case of using supercomputer resources. The paper analyzes the efficiency of parallelization of numerical solutions of the considered problems.

Numerical Study of the Implementation of an Active Control Turbocharger on Automotive Diesel Engines

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
J. Galindo ◽  
V. Dolz ◽  
A. Tiseira ◽  
R. Gozalbo
Keyword(s):  
Active Control ◽  
Numerical Study ◽  
Operating Point ◽  
Variable Geometry ◽  
One Dimensional ◽  
Engine Efficiency ◽  
Gas Dynamic ◽  
Operating Points ◽  
Engine Operating Point ◽  
Average Position

Active control turbocharger (ACT) has been proposed as a way to improve turbocharger performance under highly pulsating exhaust flows. This technique implies that the variable geometry mechanism in the turbine is used to optimize its position as a function of the instantaneous mass flow during the engine cycle. Tests presented in the literature showed promising results in a pulsating gas-stand. In this work, a modeling study has been conducted at different engine conditions aimed to quantify the gain in on-engine conditions and to develop a strategy to integrate the ACT system within the engine. Different ways of changing the displacement of the variable mechanism have been analyzed by means of a one-dimensional gas dynamic model. The simulations have been carried out at constant engine operating points defined by fixed air-to-fuel ratio for different mechanism displacement functions around an average position that guarantees the desired amount of intake air. The benefits in overall engine efficiency are lower to those predicted in the literature. It can be concluded that it is not possible to use the ACT system to optimize the turbine operating point and at the same time to control the engine operating point.

scholarly journals Solution of the turbocompressor boundary condition for one-dimensional gas-dynamic codes

2010 ◽  
Vol 52 (7-8) ◽  
pp. 1288-1297 ◽  
Author(s):  
J. Galindo ◽  
F.J. Arnau ◽  
A. Tiseira ◽  
P. Piqueras
Keyword(s):  
Boundary Condition ◽  
One Dimensional ◽  
Gas Dynamic

scholarly journals РОЗРАХУНОК ТЕМПЕРАТУРНО-ШВИДКІСНИХ ПАРАМЕТРІВ ЧАСТИНОК ПРИ ХОЛОДНОМУ ГАЗОДИНАМІЧНОМУ НАПИЛЮВАННІ

2019 ◽  
pp. 139-144
Author(s):  
Олександр Володимирович Шорінов ◽  
Андрій Олегович Волков ◽  
Сергій Євгенійович Маркович ◽  
Анатолій Іванович Долматов
Keyword(s):  
Numerical Simulation ◽  
Critical Velocity ◽  
Cold Spray ◽  
Aluminum Powder ◽  
Cold Spray Process ◽  
One Dimensional ◽  
Spray Process ◽  
Gas Dynamic ◽  
Temperature And Pressure ◽  
Nozzle Inlet

The method of computational fluid dynamics (CFD) for the supersonic nozzle SK-20 of the low-pressure cold gas-dynamic spraying equipment DYMET-405 was applied for calculation of particles impact temperature and velocity. The application of the CFD method is the one-dimensional isentropic gas-dynamic model considers the flow only along the nozzle axis, without taking into account the heat exchange with the nozzle and the friction losses on the internal walls, which leads to obtaining overestimated results of calculations. Previously it was found out that the difference in the values obtained by numerical simulation and the results of calculations of a one-dimensional isentropic model was less than 10%. Numerical simulation of the two-phase flow of the cold spray process has been performed using the Ansys Fluent Academic software package. The influence of the initial cold spray process parameters such as temperature and pressure at the nozzle inlet on the change in temperature and velocity of aluminum particles with a diameter of 25 μm at the moment of impact with the substrate has been studied. Also, the influence of the particle size on the above-mentioned parameters has been obtained. The numerical simulation results of the particle impact temperature with the substrate have been used to calculate the critical velocity of aluminum powder – the velocity needed for coating formation. It is known that the formation of cold spray coatings depends on the velocity of the powder particles. For each material, there is a critical velocity at which the process of forming the coating begins. At particle velocities above the critical one, their adhesion to the substrate and the formation of the coating, due to the plastic deformation of the particles, occurs, while at lower velocities the surface erosion or deposition with low efficiency under certain conditions is observed. As a result of simulation and calculations of the critical velocity, the window of spraying was developed, that is the region of values of velocities and temperatures of the particles of aluminum powder, depending on the temperature and pressure of the air at the nozzle inlet, at which the formation of coatings is possible.

scholarly journals Methods of determination of the gas-dynamic characteristics of a jet nozzle of an aerodynamic object

2021 ◽  
Vol 66 (3) ◽  
pp. 320-328
Author(s):  
A. Ph. Ilyushchanka ◽  
A. K. Kryvanos ◽  
A. D. Chorny ◽  
Y. Ya. Piatsiushyk
Keyword(s):  
Gas Dynamics ◽  
Modeling Method ◽  
Jet Engines ◽  
Dynamics Modeling ◽  
Dimensional Theory ◽  
One Dimensional ◽  
Modeling Methods ◽  
Gas Dynamic ◽  
Working Medium ◽  
Jet Nozzle

The efficiency of aerodynamic objects with jet engines is the result of many factors, among which nozzle parameters are of great importance in relation to the general engine design and the energy source, that determines the composition and properties of the engine working medium. In this respect, an urgent need was to calculate nozzle gas-dynamic characteristics and geometric parameters at various designing and testing stages of jet engines. Relatively simple calculations involving a large number of assumptions and detailed modeling with regard to the maximum possible number of factors are the basis of the existing modeling approaches. In the present work, the problem was to assess an agreement between such modeling methods of a specific ‘high-energy material – working medium – nozzle’ system and the experimental ones. The calculations using one-dimensional nozzle theory and the gas dynamics modeling method revealed a 6 % difference in the results of various parameters. At the same time, a closer agreement was noted between the experimental data and the results predicted by the gas dynamics modeling method. Moreover, in comparison to one-dimensional theory, the gas dynamics modeling method of an engine jet nozzle is more labor-intensive and expensive for calculations. Therefore, from the practical viewpoint, it is advisable to give preference to one-dimensional theory to calculate the engine construction and to verify calculations with the use of the modeling methods.

THE IMPACT OF THE DIMENSION OF A MATHEMATICAL MODEL OF INTERNAL BALLISTICS ON DESIGN PARAMETERS OF A SHOT FOR GRAIN GUNPOWDER CHARGES

2021 ◽  
pp. 95-110
Author(s):  
I.G. Rusyak ◽  
◽  
V.A. Tenenev ◽  
Keyword(s):  
Mathematical Model ◽  
Powder Mixture ◽  
Thermodynamic Model ◽  
Dynamic Models ◽  
Design Parameters ◽  
Variable Cross ◽  
One Dimensional ◽  
Gas Dynamic ◽  
Wide Range ◽  
The Impact

The problem of the impact of the mathematical model dimension on the calculated intraballistic characteristics of a shot for the charges made of granulated powder is considered. Mathematical models of the shot are studied using the spatial (axisymmetric), one-dimensional, and zero-dimensional (thermodynamic) formulations. The thermodynamic model takes into account the distribution of the pressure and velocity of a gas-powder mixture behind the shot for a channel of variable cross-section. Comparison of simulation results is carried out in a wide range of loading parameters. It is shown that there is a range of the loading parameters for a thermodynamic approach to give satisfactory approximation to the parameters obtained using the gas-dynamic approach, which describes the flow of a heterogeneous reacting mixture with a separate consideration of phases and intergranular interactions between them. Notably that in the entire range of the charging parameters studied in this work, the one-dimensional and twodimensional gas-dynamic models only slightly differ from each other. Therefore, in the main pyrodynamic period, the actuation of the charge, made of granulated powder, can be simulated using a one-dimensional gas-dynamic model or a zero-dimensional thermodynamic model with allowance for spatial distribution of the pressure and velocity of the gas-powder mixture.

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