In this study, the methodological foundations of the technology for the local reduction of chemical pollution from vehicles were improved through the use of twolevel suction units and guide plates of various lengths installed on the nozzles of the suction devices. A program has been developed for the numerical calculation of the carbon monoxide concentration field for evaluating the efficiency of using two-level exhaust systems with different lengths of guide plates on the gas flow selection pipes. The solution of the equations of hydrodynamics and mass transfer is carried out on the basis of finite-difference methods. A number of physical and computational experiments have been carried out; it has been established that the concentration of carbon monoxide in the zone of two-level suctions location decreases by 46-68%.
The problem of estimating the level of air pollution in the working areas near the coal pile is considered. The task is to develop a CFD model that allows to predict the level of air dust pollution, taking into account the process of wetting the surface of the coal pile. To model the process of coal dust transfer in the air, a twodimensional mass transfer equation is used, which takes into account coal dust transfer due to convection and diffusion. The Navier-Stokes equations are used to calculate the air flow field near the coal pile. Finite-difference schemes of splitting are used for numerical integration of modeling equations. Computer code is developed on the basis of created CFD model. The developed code can be used to analyze the effectiveness of the coal surface wetting to reduce dust pollution of work areas near coal piles. The results of a computational experiment are presented.
Coal trains have an intensive impact on environment pollution. It is very important to predict adequately this impact during coal transportation. In Ukraine to predict atmosphere pollution from coal trains the regulatory model «OND-86» is used. This model does not take into account some important factors and coal train movement. We present numerical models to solve two problems:1) prediction of atmosphere pollution in the case of moving coal train; 2) prediction of atmosphere pollution in the case of additional special boards installation on the coal wagon. To solve these problems equation of coal duct convective-diffusive dispersion (Lagrange model of admixture dispersion) and equation of potential flow were used. Governing equations were numerically integrated using implicit difference schemes. For coding difference equations we used FORTRAN language. We present results of numerical experiments and laboratory experiments which illustrate the efficiency of the special additional boards installation on the coal wagon. These boards have «internal wing» and «external wing». The obtained results illustrate that installation of additional boards allows to minimize the atmosphere pollution near transport corridor.
In this study, a numerical model is proposed for calculating pollution zones near the road, taking into account the geometry of the automobile transport, meteorological conditions, the location of the barriers and their height, and the chemical transformation of nitrogen oxides in the atmospheric air. The numerical solution is based on the integration of the mass transfer equations using the finite-difference method. To determine the components of the air flow velocity vector, a two-dimensional model of the potential flow is used, where the Laplace equation for the velocity potential is the modeling equation. Based on this numerical model, a software package has been developed that allows computational experiments and does not require large expenditures of computer time. Based on the results obtained, an assessment was made of the effectiveness of the use of barriers to reduce the level of air pollution near highways. It has been established that the use of barriers of different heights reduces the level of pollution behind the road by approximately 20-50%.
Purpose. The important problem in the field of ecological safety and industrial safety is providing of normal microclimate in dead-end mine working. In these regions of the mine methane gas can be accumulated and as a result explosion may take place. So, to avoid these accidents it is important to ventilate appropriately dead-end mine working. The purpose of the work is development of quick computing mathematical model to obtain information about dead-end mine working ventilation process. Methodology. The process of dead-end mine working ventilation computing is separated in two stages. At the first stage the velocity flow field is computed in the dead-end mine working. We consider the situation when the suction tube is situated in this region. To solve this problem the fluid dynamics model of inviscid gas flow was used. At the second stage of the computational modeling the convective- diffusive equation of admixture transfer was used. The equation takes into account non-uniform flow field in the dead end mine workings. Findings. The developed numerical model was coded using FORTRAN language. The developed computer code allows to perform numerical experiment to assess the efficiency of suction tube implementation to decrease methane gas concentration in dead-end mine working. Originality. The developed numerical model takes into account physical factors, which are not considered nowadays in the empirical models, which are used for solving the problems of dead-end mine working ventilation. It allows taking into account the geometrical form of the dead-end mine working. Practical value. The developed computer program allows to perform calculations to assess the efficiency of suction system used for the ventilation of the dead-end mine working.
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