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Since 1978
Published in Sarov (Arzamas-16), Nizhegorodskaya oblast |
RUSSIAN FEDERAL
NUCLEAR CENTER -
ALL-RUSSIAN RESEARCH INSTITUTE
OF EXPERIMENTAL PHYSICS |
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 Русский |  English
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Issue No 2, 2010 |
STUDY OF THE COMPUTATIONAL PARAMETERS EFFECT AT NUMERICAL SIMULATION OF THE EXPLOSIVE TRANSFORMATION PROCESS OVER MC KINETICS IN THE LEGAK TECHNIQUE
N. A. Volodina, I. Yu. Myshkina, V. F. Spiridonov
VANT. Ser.: Mat. Mod. Fiz. Proc. 2010. No 2. P. 3-14.
During numerical simulation of the detonation development and distribution process under the LEGAK technique the technology of calculations with the MC kinetics on Lagrangian-Eulerian grids was perfected. The behavior of the calculation results with the MC kinetics was studied on the gradually thickening grids. The effect of the time step, type of the calculation quadratic viscosity and mixed cells thermodynamic parameters calculation algorithm on the numerical solution is studied.
The parameters of the MC kinetics model for TATB-type explosives were specified more precisely. The calculation results for 1D and 2D problems as well as their comparison with experimental data obtained in IFV VNIIEF are presented in the paper.
Key words: LEGAK technique, MC detonation kinetics, equation of state of explosive.
| | ON THE DETERMINATION OF ARTIFICIAL VISCOSITY FOR MIXED CELL COMPONENTS E. A. Goncharov, V. Yu. Kolobyanin, Yu. V. Yanilkin
VANT. Ser.: Mat. Mod. Fiz. Proc. 2010. No 2. P. 15-29.
The paper considers several ways of artificial viscosity determination for mixed cells components with two or more materials. The dependence of the calculation results on these ways is studied on test problems for three closing methods of gas-dynamics equations using the following suppositions: the components` velocities divergences are equal, the components` pressure increments are equal, the components` mass velocities after passing weak perturbation are equal.
Key words: EGAK technique, gas dynamics, closure methods for gas dynamics equations, artificial viscosity.
| | APPLICATION OF THE TVD-APPROACH TO THE DSn-METHOD FOR THE HEAT RADIATION TRANSPORT EQUATION SOLUTION IN THE AXIALLY-SYMMETRIC RZ-GEOMETRY A. D. Gadzhiev, V. V. Zavyalov, A. A. Shestakov
VANT. Ser.: Mat. Mod. Fiz. Proc. 2010. No 2. P. 30-39.
Realization of the implicit nonlinear TVD-type scheme of a higher approximation order is considered for the solution of the heat radiation transport equation in the axially-symmetrical RZ-geometry on arbitrary quadrangular grids in the frames of the discrete ordinates. A limiter is used in the scheme, which is calculated explicitly over the values known from the previous time step on a three-point template in each direction. This property allows application of the time-saving sweep computation for the solution of the system of difference equations. The scheme combines conservativeness, smoothness in the sense of the TVD-scheme methodology, first order approximation over time and second order approximation over space, except several points with extremums. The order of approximation is studied for a model transport equation. Earlier this scheme was tested for 1D geometries. The results of test problem numerical calculations are presented.
Key words: radiation transport, difference scheme, method of discrete ordinates, TVD approach.
| | SELF-SIMILAR HEAT WAVES FROM A CONCENTRATED OR SPATIAL SOURCE IN AN ENVIRONMENT WITH NON-HOMOGENEOUS THERMAL-PHYSICAL PARAMETERS B. P. Tikhomirov
VANT. Ser.: Mat. Mod. Fiz. Proc. 2010. No 2. P. 40-50.
The problems about an instantaneous concentrated source in an environment with distributed physical parameters, as well as the problem about a special spatial source are considered. The issue of joining known self-similar solutions on the plane interface of environments with different thermal-physical characteristics is discussed in the paper. The obtained conditions of solutions` agreement allow us to estimate the part of the released energy to the left and to the right from the interface surface.
In the problem about a spatial source the combustion function, proportional to the energy and inversely proportional to the time, was taken as the source. Note, that this problem includes the problem of instantaneous concentrated source as a particular case.
The precise solution was built with account for the radiation energy density for setting the problems with planar, cylindrical and spherical symmetries and the mentioned combustion function.
The examples of model problems for testing the calculation techniques of non-linear thermal conductivity in non-homogeneous environment without account and with account for the combustion function are given in the paper.
Key words: concentrated and spatial sources, thermal wave, interface, matching of self-similar solutions, model test problems.
| | SOLUTION TECHNIQUE FOR NEUTRON AND GAMMA-QUANTUM TRANSPORT EQUATION AT TABULATED INPUT SCATTERING GROUP CROSS-SECTIONS AND ITS APPLICATION FOR THE VVER-1000 REACTOR PROTECTION O. V. Nikolayeva, L. P. Bass, V. S. Kuznetsov, V. V. Sinitsa, V. I. Tsofin
VANT. Ser.: Mat. Mod. Fiz. Proc. 2010. No 2. P. 51-63.
An algorithm able to find solutions of the multi-group radiation transport equation in multi-dimensional geometries with tabulated input scattering cross-sections is presented in the paper. The algorithm verification results obtained on a trivial model problem with smooth model scattering cross-sections are discussed. The paper presents neutron and gamma flux densities calculated using the scattering cross-sections, which satisfy the real laws of radiation/matter interaction in a small model problem with a point isotropic mono-energy source and protection of the VVER-1000 reactor area. It is shown in the paper how the flux densities change when passing from the tabulated input data to their polynomial representation.
Key words: transport equation, angular dependence of scattering cross-sections.
| | A COMPUTATIONAL MODEL OF SOLUTION CRYSTALLIZATION UNDER CONTROL ACTION OF TEMPERATURE FIELD FOR THE CASE OF BIOCRYSTAL GROWTH V. P. Ginkin, S. M. Ganina, O. M. Ginkina
VANT. Ser.: Mat. Mod. Fiz. Proc. 2010. No 2. P. 64-74.
A computational model was built and the numerical study of the protein crystallization (lysozyme) out of a water solution under the impact of a precipitant (NaCl) concentration spatial distribution and controlling point-wise temperature impact was performed. The computational model describes the generation of the crystal nuclei and their growth depending on the oversaturation local value as well as on the heat-mass transport in the whole solution area including the protein crystals. The heat-mass transport is described by the Navier-Stokes equations in the Boussinesq approximation with account for the thermogravitation and concentration convections.
Key words: protein crystallization, lysozyme, mathematical crystallization model, precipitant, equilibrium solubility, solubility as a function of temperature, oversaturation, convection, Navier-Stokes equation, computational algorithm, growth rate control, point-wise temperature impact.
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