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Vol. 18 (2015 year), No. 2
Kozyrev S. A., Skorokhodov V. F., Nikitin R. M., Amosov P. V., Massan V. V.
Assessment of aerological setting in open mining
based on 3D open-pit model
3D modeling in ANSYS Fluent software has been used to research air flows distribution character on surface and in deep open-pit space with taking into account actual local relief and open-pit scale. This has allowed revealing influence of rock dumps and near-wall pit zones on generation of recirculated zones and turbulent flows, and extent of air flows weakening in different open-pit zones depending on wind velocity on surface
(in Russian, стр.5, fig. 6, tables. 0, ref 4, Adobe PDF, Adobe PDF 0 Kb)
Vol. 19 (2016 year), No. 1, DOI: 10.21443/1560-9278-2016-1/1
Masloboev V. А., Baklanov А. А., Amosov P. V.
Results of evaluation of tailing dumps dust intensity
A set of most acceptable and well-known methods of dust intensity evaluation has been defined and tested (dependence of Westphal D. L. et al. and DEAD scheme) based on the analysis of exiting approaches (deserts, tailing dumps, etc.). The description of the chosen methods has been given. The determination of dynamic velocity u* and velocity at the height of +10 m above the dusting surface u10 which are necessary to evaluate the dust intensity has been demonstrated. The method is based on two-dimensional numerical model of atmosphere aerodynamics in the area of "tailing dumps of ANOF-2 - the town of Apatity". The study provides calculations of horizontal velocity at the height of +10 m above the dusting surface at the wind speed varying from 5 to 23 m/sec. The work also suggests the results of graphical data processing related to tailing grain size distribution from the surface of the firmly established surface of the tailing dumps of ANOF-2. Comparative analysis has been given and the peculiarities of interval (based on grains sizes) dust intensity of the tailing dumps of ANOF-2 have been shown using the dependence of Westphal D. L. et al. and DEAD scheme within the wind speed range. The received values of dust intensity at the lower range limit are close to the "maximum specific dust off" value which is used by project specialists for documentation development
(in English, стр.0, fig. 0, tables. 0, ref 0, Adobe PDF, Adobe PDF 0 Kb)
Vol. 19 (2016 year), No. 1, DOI: 10.21443/1560-9278-2016-1/1
Melnikov N. N., Amosov P. V., Klimin S. G., Novozhilova N. V.
Estimation of thawing cryolithic area with numerical modeling in 3D geometry while exploiting underground small nuclear power plant
The paper presents results on 3D numerical calculation of a thermal task related to assessing a thawing area when placing modules with reactor and steam-turbine facility of a small nuclear power plant in thickness of permafrost rocks. The paper discusses influence of the coefficient of thermal conductivity for large-scaled underground excavations lining and cryolithic area porosity on thawing depth and front movement velocity under different spatial directions
(in Russian, стр.0, fig. 0, tables. 0, ref 0, Adobe PDF, Adobe PDF 0 Kb)
Vol. 20 (2017 year), No. 1, DOI: 10.21443/1560-9278-2017-20-1/1
Kozyrev S. A., Amosov P. V.
Estimation of aeration time in blind excavations: Methodological approach based on 3D numerical modeling
The paper presents the results on 3D numerical modeling of ventilation in blind excavations of different length under the fixed transverse section due to turbulent diffusion. Aerodynamic characteristics have been calculated using the standard (k – ?)-model of turbulence. The ventilation in an excavation has been simulated by numerical solution of a convectional-diffusion equation of admixture transfer. Numerical experiments of ventilation a blind excavation with 10–20 m length have been performed for range of air consumption in a through excavation from 6.25 to 50 m3/sec. Initial contamination of the atmosphere in the blind excavation has been taken in the range of 15–25 MPC (in nitric oxides). For boundary conditions observed there have been received spatial distributions of the velocity field and coefficients of turbulent viscosity in the excavation's length. The authors have revealed significant heterogeneity of the velocity field in the blind excavation and low values of velocity vector's components close to a face; this leads the turbulent diffusion mechanism to a prevailing position in the admixture dispersion. The paper presents examples of admixture distribution in excavations' space at the moment of the MPC level achievement in the blind excavation depending on the values of the model's varying parameters. It has been established that the ventilation time under otherwise equal conditions depends significantly on amount of air supplied to the main excavation. It has been shown that at initial and boundary conditions adopted the forecast of ventilation time for blind excavations through the turbulent diffusion mechanism can be performed based on integrated analytic correlation with such arguments as excavation length, air consumption and initial level of gas contamination. The analysis of numerical test results performed on the basis of 3D models designed has shown that the blind excavations with length more 10 m where stoping operations are running can be ventilated due to the turbulent diffusion mechanism. Time of the blind excavation ventilation in dependence of gases concentration in it can reach more than two hours in dependence of volume of air supplied in a through excavation.
(in Russian, стр.8, fig. 5, tables. 3, ref 4, Adobe PDF, Adobe PDF 0 Kb)
Vol. 24 (2021 year), No. 2, DOI: 10.21443/1560-9278-2021-24-2
Amosov P. V.
Numerical simulation of the thermal regime of an underground spent fuel storage facility (built-in structure variant)
The results of a numerical simulation of the thermal regime of an underground facility for long-term storage of spent nuclear fuel in a built-in reinforced concrete structure are presented. Two computer models were constructed in a three-dimensional formulation in the COMSOL programme. The first model is based on the incompressible fluid approximation, while the second model is based on the "incompressible ideal gas" approximation. The mathematical basis of models: the continuity equation, Navier – Stokes equations averaged by Reynolds, the standard (k – ?) turbulence model, and the general heat transfer equation. Consideration of mixed convection conditions is implemented in the "incompressible ideal gas" approximation, where the air density is a function of temperature only. The most thermally stressful arrangement of spent fuel placement is investigated: U-Zr – defective – U-Be. The air rate is varied in the range from 21 to 0.656 m3/s. Numerical experiments were performed for up to 5 years of fuel storage. The principal difference between the non-stationary structure of the velocity fields predicted in the "incompressible ideal gas" model and the "frozen" picture of the aerodynamic parameters in the incompressible fluid model is emphasized. It is shown that the requirements for exceeding the temperature limit values are met when the object operates under conservative ventilation conditions (rate 0.656 m3/s) with a minimum of costs for organizing ventilation. The dynamics of heat flows directed into the rock mass through the base and from the surface of the built-in structure of the U-Zr fuel compartment to the air environment are analyzed. The predominance of the heat flow from the surface of the structure and the different times when the curves of the heat flow dynamics reach their maximum values are noted. The heat flow to the array reaches its maximum significantly faster than to the air.
(in Russian, стр.11, fig. 6, tables. 4, ref 25, AdobePDF, AdobePDF 0 Kb)
Vol. 25 (2022 year), No. 1, DOI: 10.21443/1560-9278-2022-25-1
Amosov P. V., Baklanov A. А., Makarov D. V., Masloboev V. А.
Numerical modeling of atmospheric pollution in the approaches of random selection of discrete dusting sites and interval distribution of dust size
The results of numerical simulation of atmospheric pollution in Apatity are presented with variations in the dusting area of discrete spatially spaced areas selected randomly and the wind flow velocity. CFD modeling in the volumetric formulation was performed using the COMSOL program. To calculate the aerodynamic characteristics, an incompressible fluid approximation was used using the standard (k-?) turbulence model. The process of fine dust propagation is modeled by numerical solution of the convective-diffusion impurity transfer equation taking into account the deposition rate. Numerical experiments (with a total number of more than 1,400) were carried out with a variation of the wind flow velocity from 5 to 23 m/s and a dusting area from 2 to 10 ha with a random selection of 20 discrete sites. Dynamic velocity distributions for specific areas of dusting, interval and total spatial distributions of dust pollution (dust particles with a diameter from 0 to 70 microns in increments of 10 microns) are obtained. The peculiarities of the influence on the levels of atmospheric pollution of specific areas of Apatity depending on the location of dusty areas on the surface of the beach of the tailings dump are noted. The calculated levels of atmospheric pollution in the center of Apatity averaged by the number of combinations of dusting sites are analyzed and generalized to functional dependencies. The calculated dependences of the dust concentration on the dusting area at a fixed wind speed are described by linear functions. The dependence of the dust concentration on the wind flow velocity at a fixed dusting area can be approximated by a power function. The generalized functional dependence makes it possible to predict the dust concentration in Apatity depending on the dusting area of randomly selected discrete areas on the surface of the tailings dump and the wind flow velocity. The obtained dependence permits to make a forecast of the critical dusting area at which the level of atmospheric pollution reaches the maximum permissible concentrations, depending on the speed of the wind flow.
(in Russian, стр.13, fig. 4, tables. 5, ref 32, AdobePDF, AdobePDF 0 Kb)
Vol. 26 (2023 year), No. 1, DOI: 10.21443/1560-9278-2023-26-1
Amosov P. V., Baklanov А. А.
Development of a model of atmospheric aerothermodynamics for the study of dusting processes at tailings dumps using COMSOL software
An overview of studies of aerothermodynamics and atmospheric pollution at mining facilities using computational fluid dynamics software systems (CFD modeling) has been presented. Both specialized and non-specialized software are marked. The review focuses on the studies performed using the FLOWVISION, ANSYS FLUENT and COMSOL software codes. An aerothermodynamic model of the atmosphere is described in which the equations of dynamics in the incompressible fluid approximation are supplemented by the heat transfer equation and the parameters of Coriolis, convection (buoyancy), background stratification and radiation flux. The necessary modifications in the COMSOL software are described, which make it possible to carry out studies of atmospheric aerothermodynamics under various atmospheric conditions. A two-dimensional CFD model of the atmosphere has been built and tested on a simplified representation of the tailings dump. At a fixed wind flow velocity of 5 m/s and variations in the background stratification parameter (from –0.05 to +0.05 °C/m), numerical experiments have been performed and the calculation results have been analyzed. Differences in the aerodynamic parameters of the flows and the spatial distribution of temperature under different atmospheric conditions are noted. Estimates of the dynamic velocity at the dusting height and the vertical mass flux using the empirical dependence of the dusting intensity are performed. The analytical dependence of the vertical mass flux as a function of the stratification parameter is discussed. The asymmetry (relative to the neutral state of the atmosphere) of the magnitude of the vertical mass flux in comparison with the unstable and inversion states is shown. In stable atmospheric conditions, the magnitude of the vertical flux of the dust mass, and hence the pollution of the atmosphere downstream, will be noticeably higher than in unstable states.
(in Russian, стр.19, fig. 5, tables. 3, ref 50, AdobePDF, AdobePDF 0 Kb)