The production of aluminium using the Soderberg technology is accompanied by the formation of a large number of harmful emissions, including in the anode gas. In this paper, a study of the technology for reducing harmful emissions during anode gas afterburning was conducted based on three-dimensional mathematical modeling. A numerical method has been developed to describe the process of anode gas oxidation in the presence of a jet of superheated steam as applied to the gas collection dome of an aluminum electrolyzer. For the first time, a comparative analysis of the influence of superheated steam on the combustion characteristics of anode gas and the level of harmful emissions has been carried out. It was found that increasing the steam concentration in the active combustion zone increases the rate of chemical reaction of interaction of anode gas and OH radicals. The results of the study showed that the greatest effect in reducing CO emissions is observed at a steam to anode gas ratio of 35% (for this formulation of the problem).

This publication presents the results of predicting the bioclimatic level of comfort in the conditions of urban development using numerical modelling methods. The object of the study is the development of the campus of Perm State Research University, where there is a systematic activity of pedestrians in the street spaces between the academic buildings. Prediction of the comfort level of the environment was carried out for the summer period. Bioclimatic assessment was carried out using the indicator of equivalent-effective temperature. This indicator takes into account the complex influence of temperature, air humidity and wind speed on a person. The obtained results allowed us to determine that sufficiently comfortable conditions with permissible wind-temperature load on the human body are formed on the territory under consideration.

The paper considers the aerodynamics of flow around a cubic model building. Experimental and simulation data were compared for the flow problems with different scales. Geometry parameters for the models can be varied from 0.025 to 6 m, while the range of Reynolds number for considered data is from 104 to 106. The scalability of the modeling is confirmed, which is beneficial for validity of laboratory aerodynamic experiments.

In the present paper, a computational study of the influence of solar and thermal radiation on the formation of wind and temperature conditions in urban environment is carried out using the example of an urban area of Krasnoyarsk in winter. For calculations, a developed microscale mathematical model of urban atmosphere was used. The calculation results showed that the presence of radiation in the daytime leads to an increase of temperature and average speed of wind, as well as to the formation of an unsteady wind regime in urban environment.

The paper deals with the numerical study of aerodynamics and heat transfer for a case of a four-vortex furnace chamber designed for jet fire of brown coal from the Eastern-region coalfields. The combustion modeling is achieved by a set of linked submodels: they describe turbulent gas flow, thermal and radiative heat transfer, processes of degradation and burning for coal particles, and NOx generation. Simulation demonstrated that using of these types of brown coal in a specific-design furnace chamber creates a steady four-vortex flow structure that provides a uniform temperature field in the volume and admissible generation of NOx.

In this paper, the co-combustion process of coal-water slurry (CWS) and pulverized coal fuel (PCF) in E500 pilot boiler when using staged afterburning scheme, was investigated based on numerical simulation. A complex three-dimensional mathematical model and numerical methodology was used to describe the CWS and PCF co-combustion, as well as subprocesses in the combustion chamber. The proposed mathematical model was tested based on data obtained from a full-scale experiment. A good compliance was shown between the computational results and the experimental data. A detailed comparative analysis of the effect of changes in the design of a pilot boiler when using a three-stage combustion scheme and the flare-drip combustion technology for CWS on the physical-chemical processes in the combustion chamber and environmental indicators was carried out for the first time. The change of circulation zones depending on the method of coal fuel supply during three-stage combustion was investigated. Calculations have shown that the implementation of the proposed changes reduced the underburning of solid carbon from 1.9% to 0.51%. It was revealed that using CWS as a reducing agent diminishes the amount of harmful NOx emissions by more than 40% compared to the basic version.

The paper presents the results of development and study of an aerodynamic wall made with industrial axial fans as a tool for conducting of laboratory experiments to study the aerodynamics of various objects, including the testing of drone flight modes. Preliminary calculations, which showed the feasibility of creating an aerodynamic wall in the form of 4x4 or more fan array, were carried out using CFD modeling. A model aerodynamic wall of 4x4 server fans has been created and the characteristics of the output flow have been studied, including the confusers effect to increase the output speed. Based on the results of preliminary work, an aerodynamic wall in the form of an array of 4x4 industrial axial fans type VO-6-300-4 was developed and manufactured. The outlet section is 3.7 m2, an outlet flow rate of up to 10 m/s (14 m/s when using a confuser) and a total power consumption is 12 kW. The use of several frequency changers to control the rotation speed of the fans allows make possible control the output flow profile, which is important in a number of scientific areas.

A simple criterion for evaluating the grid resolution needed to obtain a grid-independent solution of turbulent flow problems in the framework of statistical approach to turbulence simulation is proposed. The criterion is derived on the basis of an a posteriori estimate of the local interpolation error of the field of turbulent kinetic energy. A good resolution should ensure a small local interpolation error of the discrete turbulent kinetic energy. The equation for the transport of turbulent kinetic energy and realizability conditions for the turbulent stress tensor made it possible to reduce the estimation of relative interpolation error to an explicit formula for the estimate of the maximal grid step required for obtaining a grid-independent solution. The proposed criterion is applied to a steady problem for a flow past a backward facing step and to the problem of unsteady flow around a half-circular profile arranged at a zero angle of attack for the Reynolds number Re = 45 000. A numerical study showed that the proposed criterion gives a good estimate of the grid resolution required for obtaining a grid-independent solution away from a wall. This criterion can be used both for estimating the grid independence of the solution and for adapting the computation grid.

A mathematical model developed to describe the interaction of a thermal convective flow with a moving body is presented. The model was implemented within the framework of the SigmaFlow computational software package, which is based on computational fluid dynamics methods. The thermal convective flow is described by the Navier–Stokes equations in the Boussinesq approximation, and the moving body model is implemented using the immersed boundary method. The article presents the results of verification of the proposed mathematical model by solving the following test problems: unsteady laminar flow around the cylinder; natural convection in the channel between two cylinders; developed convective flow in a closed rectangular area with a fixed plate. The results of a numerical study of the plate motion in a thermal convective flow in a closed volume (cuvette) with hot lower and cold upper walls are presented. The calculations showed that the moving plate has an impact on the dynamics of formation of large-scale cells, the local distribution of heat flux density on the lower wall and the integral heat flux. In particular, they revealed a local decrease in the heat flux under the plate, an increase in the number of large vortices in the cuvette and the destruction of the horizontal temperature gradient observed in the case of a fixed plate. In addition, for a fixed plate, the value of heat flux under it depends on its position, and in the case of a moving plate – on the position and direction of its movement. A qualitative comparison of calculations for two different Rayleigh numbers with the experimental data obtained at the Institute of Continuous Medium Mechanics of the Ural Branch of the Russian Academy of Sciences showed that the behavior of the plate is governed by similar regularities.

The paper presents the results of a numerical forecast of the pedestrian comfort level in the territory of urban development. The research uses the microscale numerical model of the atmosphere in the urban environment, into which the equations of temperature and seasonal indices are integrated. These equations are used to simulate and analyse pedestrian comfort conditions. The paper presents the results of the proposed model approbation in the real environment of the residential neighbourhoods of Krasnoyarsk city. External conditions, typical for summer and winter seasons, were simulated. The results produced are presented as distribution fields of the considered indices. During the analysis, comfortable/discomfort areas for humans staying in the environment of studied urban development were revealed.

Numerical studies of the processes of oxy-fuel combustion of pulverized coal (PC) in an industrial boiler BKZ 500-140-1 (with a capacity of about 400 MW) were carried out in this work. The proposed comprehensive mathematical model was tested based on data from a full-scale experiment (2.4 MW laboratory stand) of oxy-fuel combustion of PC. The conducted comparison has shown a good agreement of the calculation results with the experimental data. A detailed comparative analysis of the effect of the operating modes of the BKZ 500-140-1 industrial boiler during oxy-fuel combustion of coal on physical and chemical processes and the level of harmful emissions (NOx, CO2) was performed for the first time. The effect of oxygen concentration and CO2/H2O ratio in the blast on the processes of ignition and combustion of fuel in a nitrogen-free environment has been studied. It is shown that when nitrogen in the blast composition is replaced with flue gases without changing the oxygen concentration in the boiler under study, the average temperature in the furnace volume declines, as well as the average heat flux at the walls decreases from 87.35 to 70.32 kW/m2. To achieve the standard operating pa-rameters of the BKZ 500-140-1 industrial boiler, it is necessary to increase the oxygen concentration in the blast from 15.4 to 19.7 vol.% (i.e. by 28%). The implementation of the oxy-fuel combustion technology on a steam boiler leads to a decrease in the NOx concentration in flue gases from 480 to 273 mg/m3.

Currently, thermal power plants operating on hydrocarbon fuels (gas, fuel oil, peat, shale, etc.) are one of the main sources of electricity. An effective and promising method for suppressing harmful emissions (NOx, carbon oxides, soot) from the combustion of fossil fuels is the injection of steam into the combustion chamber. The influence of various mathematical submodels was studied on the accuracy of the numerical simulation of the process of n-heptane combustion in a laboratory burner with steam additive to the reaction zone as a promising chemical engineering method for the disposal of substandard liquid fuels and combustible waste with the production of thermal energy. The problem was solved in a three-dimensional stationary formulation. Systematic verification of these submodels, and a comparison of the results of the calculation with the experimental data obtained were carried out. The comparison with the experimental data was carried out for gas components and temperature distribution at the burner outlet; high agreement of the results was achieved. Optimal submodels of the methodology for calculating the process of fuel combustion in a jet of steam were determined. The best agreement with the experiment data was obtained using the EDC model in combination with a mechanism consisting of 60 components and 305 elementary reactions. More correct simulation results were obtained using the RSM turbulence model and the DO radiation model.

The article is devoted to numerical simulation of diesel and pulverized coal flaring in a small-sized furnace with a vortex oil-steam burner. The results of modeling a small-sized combustion chamber with a steam-oil burner operating in combination with diesel fuel and micro-milled coal are presented. The simulation results showed that the combustion chamber with a steam-oil burner works stably in a wide range of coal dust flow rates. The obtained results of a numerical study can be used in the design of a new burner and furnace device, choosing the optimal operating modes to reduce the concentration of harmful emissions and fuel underburning at the output.

The present paper reports on the numerical simulation of flow dynamics in a model gas-turbine combustor by large eddy simulation in order to evaluate the effect of coherent flow structures on the local fluctuations of gas temperature and local concentrations of NO and CO. The simulations were performed for a generic swirler, based on the design by Turbomeca, for a Reynolds number of 15,000 at normal and elevated inlet temperature and pressure (up to 500 K and 3.4 atm). The simulation data were validated based on the velocity measurements by stereoscopic particle image velocimetry. In order to reveal coherent flow structures, the velocity snapshots were processed by the proper orthogonal method. The temporal coefficients of the decomposition were used to evaluate the conditional sampled spatial distributions of the temperature and species concentration. It is shown that the coherent fluctuations of temperature can locally reach up to 200 K with the fluctuations of NO up to 20%. Thus, the results demonstrate that coherent flow structures in a lean swirl combustor can sufficiently contribute to NOx emission.

In the present paper, the process of co-combustion of coal-water slurry (CWS) and pulverized coal fuel (PCF) in the E500 pilot-industrial boiler employing a stepwise arrangement of afterburning is investigated based on numerical simulation. To describe the CWS and PCF co-combustion, the authors used a model of the motion of a multicomponent non-isothermal gas medium (carrier phase) based on the RANS approach, a model of droplet/particle motion based on the Lagrange approach, and a model of combustion in the gas phase based on a hybrid model. The proposed comprehensive mathematical model was tested based on data from a full-scale experiment. For the first time, a detailed comparative analysis of the impact of changes in the design of a pilot-industrial boiler, using a three-stage arrangement of combustion and the flare-drip combustion technology for CWS on the physicochemical processes in the combustion chamber and environmental indicators was carried out. The change of circulation zones depending on the coal fuel supply method during the implementation of three-stage combustion was investigated. It has been revealed that using CWS as a reducing agent allows reducing the amount of harmful NOx emissions relative to the basic version by more than 40%.

The results of numerical modeling of the influence of geometric characteristics of snow-protecting fences on the intensity of snow deposition at the initial stage of formation, that is, without taking into account the influence of the dynamics of the shape of the snow cover surface, are presented. In the most industrialized and densely populated region on the Arctic Krasnoyarsk Territory - the industrial City of Norilsk, daily snowfall can exceed 50 mm, the snow depth reaches, on the average, 47 cm (the largest is 70 cm), while the wind speed - 25-30 m/s. This promotes formation of snow deposition on roads, in residential areas as well as in industrial sites and infrastructure facilities, which hampers and sometimes completely stops operation of them. As part of the solution of these problems, a software package has been developed aimed at numerical modeling of snow transport processes and implementing the snow protection measures. To simulate the dynamics of the wind-induced snow drift, a microscale model of the atmospheric boundary layer was used together with a diffusion-inertial description of the transport of the snow dispersed phase. Analysis of the calculation results shows that the width of the plates, as well as their spatial orientation, have insignificant effect on the snow-holding capacity of fences. The size of the gaps between the rails and the height of the lower gap exerts the greatest influence on the distribution of the intensity of snow deposition, both on the leeward and windward sides of the fence. In general, we can talk about the relationship between the wind speed field formed during the drift around the fence and the distribution of the snow deposition intensity. Thus, a relative decrease in the average wind speed from the leeward side of the fence increases the precipitation intensity. The presented results of numerical modeling do not contradict data of field observations previously obtained by other authors, and, thus, the developed software package allows comparing effectiveness of different snow-protecting constructions.