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%.
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 scientific work is devoted to the development of a new method for forecasting aeroionic mode in working areas at industrial sites, taking into account ionizing sources and surrounding obstacles. Methodology. To find the concentration of positive aeroions, dust and negative aeroions, we use 3D mass transfer equations that take into account the rate of recombination of ions having different polarity and the rate of recombination of ions with dust particles. The numerical solution is based on the integration of the mass transfer equations using the finitedifference method, which turns out to be stable for any step in time. To determine the components of the air velocity vector, a three-dimensional model of the potential flow is used, where the Laplace equations for the velocity potential are the modeling equations. Findings. The mathematical method of numerical calculation of the concentration of positive, negative aeroions and dust has been developed. A feature of the method is the possibility of predicting the aeroionic mode, taking into account all physical factors that significantly affect the formation of concentration zones of aeroions in working areas at industrial sites. The method is not tied to a particular industrial site, it allows us to estimate the value of the concentration of aeroions both locally and in the entire calculated region. Originality. A method for prediction of aeroionic mode in working areas is developed based on 3D modeling of the propagation of negative, positive aeroions and dust under the influence of wind and diffusion, which allows to obtain results at each point of space or in a specific cross-section. Practical value. The proposed method of forecasting was used to solve the problem of estimating aeroionic mode in industrial zones in the open area of the industrial site of the Dnipro oil extraction plant in the presence of emission sources: positive aeroions during the operation of vehicles and respiration of workers; dust during the movement of workers and vehicles; negative aeroions of the ionizer installed in the working zone. The regularities of changes in the concentration of aeroions of various polarity and dust at a height of 1.7 m are determined, which corresponds to the position of the respiratory organs of workers. Quantitative results are needed in assessing the permissible working conditions in the workplaces of industrial sites of enterprises when creating new jobs and reengineering existing ones.
Purpose. Rock dumps are long-term sources of air pollution. A significant amount of harmful substances enters the atmosphere. Particularly intense is the pollution of atmospheric air due to dusting dumps. An important task is the development of methods for predicting the dynamics of atmospheric air pollution during the emission of harmful impurities from dumps. When developing methods for predicting the dynamics of air pollution from dumps. It is very important to create a universal model that would allow on a single computing platform to calculate the process of atmospheric air pollution for various impurities that are released from dumps. Another important problem is the choice of the place for optimal placement of future dumps in order to minimize their negative impact on the environment. Methodology. Numerical modeling of the formation of atmospheric pollution zones near rock dumps is based on the application of the equation of turbulent dispersion of an impurity in the atmosphere. To solve the problem of choosing the rational location of the dumps, the conjugate equation is used. Numerical integration is carried out using an implicit difference scheme. Findings. Numerical models are developed. The first numerical model allows one to evaluate the effect of rock dumps on air pollution. The second numerical model allows, on the basis of a one-time calculation, to determine the rational location of the future dump from the point of view of its minimal impact on air pollution. Originality. Two numerical models are proposed that are based on the application of the turbulent diffusion equation and the conjugate equation. These models make it possible to quickly determine the effect of rock dumps on air pollution. The models take into account the convective transport of the pollutant, atmospheric turbulent diffusion, the intensity of the emission of impurities from the dump. Practical value. The developed numerical models are implemented in the form of program codes. These program codes can be used when performing serial calculations on computers of low and medium power, i.e. computer technology, which is available to organizations involved in environmental issues in technologically saturated regions. When carrying out calculations based on the constructed numerical models, typical initial data are used regarding the intensity of the emission of impurities from dumps, weather conditions characteristic of a specific region of the country.
Tailings formed during the mining and beneficiation of iron ore are sources of intensive dust generation. In order to assess the intensity of dust formation and determine the effectiveness of methods of its reduction, it is necessary to know the local velocity of the air flow near the various surfaces of the tailings storage facility. For the theoretical solution of this problem, a CFD model was developed, which allows determining the velocity field of the air flow when flowing around the tailings storage facility. The model allows you to obtain the value of the wind speed near the surfaces of the structure and, based on this information, to make a forecast of possible dust formation. The constructed CFD model is based on the use of an aerodynamic model of potential motion. The modeling equation is the Laplace equation for the velocity potential. To build a numerical model, the idea of establishing a solution in time is used, therefore numerical integration of the “unsteady equation” for the velocity potential is carried out. Numerical integration is carried out using the finite-difference method of total approximation. The results of the computational experiment are presented.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.