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In this paper, the Discrete Element Method of simulation was used to study the catalytic granule size effect on the efficiency of a bed reactor for the ethylbenzene dehydrogenation reaction. The model constructed for the laboratory experiment was made of catalyst granules of lengths 3, 6 and 9 mm, and diameters 2.8, 3, and 3.2 mm. A detailed evaluation of the catalyst total surface area and porosity effect was conducted owing to the analysis of particles size effect on the packing. Different results were observed for a wide feed gas mixture rate. Calculations performed allowed to deduce dependences of the reaction product concentration, the pressure drops, and the reactor productivity for all the particle sizes investigated.

Open cell metal foams are promising materials for increasing heat transfer due to their tortuosity and developed surface area in car engine cooling. A new method of heat transfer intensification in open cell foam materials is proposed. The effect of micropores on the hydrodynamics and heat transfer of open cell foam material is studied. Three models of porous media were created. In the first case, the initial model with a porosity of 0.7. In the second, with the addition of micropores, the porosity became equal to 0.85. Thirdly, the porosity is 0.85, but without micropores. A micropore model was created by subtracting spheres from the framework of open cell foam. In all cases, the porous medium consists of many intersecting spheres. Numerical modelling of gas flow and heat transfer in a porous medium is performed by the control volume method in the ANSYS Fluent software package (v. 19.0) Research results can help create new types of heat exchangers.

Industrial wastewater containing oil fraction is the main type of pollution of most railway transport enterprises during external and internal washing of rolling stock, water pressure testing of its components, and parts. Wastewater is also a problem for ships that are equipped with sufficiently effective technical means of cleaning from oil products, waste steam condensates, and contaminated water in engine rooms. In sea and land transport, various separators are used to purify industrial water from oil products using coalescence and gravity separation mechanisms. However, heavy oil makes it impossible to use the gravity separation mechanism even when the emulsion is heated. One solution for efficient separation is to pass a water-in-oil emulsion through a granular or open cell foam material. The article is devoted to an experimental study of the separation of a water-oil emulsion passing through various coalescents: open cell foam material and slotted grids that can be one of the effective methods of separation. Analysis of the results showed that the open cell foam material improves the separation efficiency for low flow rates. Simultaneously, for high flow rates of the water-oil emulsion, slotted grids are more effective due to the laminarization of the flow.

A comparison of the efficiency of the open cell foam (OCF) models is carried out. Geometrical models are constructed by the methods of simple cubic, body-centered cubic, and face-centered cubic. The parameter of the material efficiency is defined as the composition of the material surface area and the gas residence time in the porous media. The analytical evaluation shows different values of effective porosity for different construction models of the material. In this case, for all considered models, the effective porosity is in the range of 0.741-0.821.

In the work, by means of numerical modeling, the influence of the size and shape of the catalyst granules in the fixed-bed reactor for the dehydrogenation of ethylbenzene to styrene on its efficiency is studied. ANSYS Fluent 19.0 software was used to solve a written system of equations. Many component properties parameters are taken from the database of the used software. The granular layer is based on the discrete element method (DEM). The granules are in the shape of a circle, trefoil, and quatrefoil and have a size of 3 mm in diameter. The length of the studied granules is 3 mm, 6 mm and 9 mm. The effect of the granule size and their shape on the concentration of product yield in a wide range of gas velocities is compared. Variants of the catalyst granules shape that provide the highest values of the reaction product output are determined. The output concentration of the product is estimated for industrial reactors and laboratory plants.

In this work, a detailed numerical simulation of the gas flow through a heated open cell foam material was carried out. For this, several models of porous media were created with several values of porosity and the same surface area. Numerical studies were carried out in the ANSYS Fluent software package. The calculations used the SST turbulence model. The validity of the use of this model was confirmed based on direct numerical calculations performed on several models with a detailed breakdown of the grid (60 million cells). Good agreement was found between the results of calculations using DNS obtained on a detailed grid and a relatively rough network with the SST turbulence model. While maintaining the surface area of the material, porosity only affects the pressure drop while keeping the heat transfer characteristics. Creating heat exchangers from porous structures while maintaining thermal characteristics and low hydrodynamic resistance will be useful when using forced convection.

One of the problems of the modern world is air pollution by harmful substances contained in the exhaust gases of cars. To solve this problem, diesel, and gasoline porous particulate filters are used. However, it is necessary that the porous filter create a minimum pressure drop while maintaining a high filtering capacity. The purpose of the study is to identify the feasibility of a discrete arrangement of filters to reduce the pressure drop. In this work, we carried out a study to determine the pressure drop in porous filters with porosity values ε=0.75 and ε=0.58. Experiments on measuring the pressure drop were carried out for a different number of filters (from 2 to 5), arranged continuously and discretely.

A numerical study of the fluidized bed industrial reactor in the presence of various internal elements is carried out by CFD methods A simple reactor heating efficiency function of chemical reaction with heat absorption is considered. The main emphasis is placed on the circulation flows of the catalyst particles and heating of the reactor. The analysis of the impact of various design elements on the heating efficiency of the reactor is carried out. Particular attention is paid to the possibility of baffles applying, which allows redirecting the flow. This effect may have an especially important value when the rapid heating of the reactor is required for temperature dependent reactions. The influence of heated catalyst feeder design on the efficiency of whole reactor heating is educed. The influence of the fractional composition of the catalyst, namely the presence of fine particles, on the reactor heating efficiency for different reactor design features is also studied. The results are carried out for a specific reactor example, but contribute to the overall branch of fluidized bed engineering.

The paper addresses approaches to increasing the efficiency of wind turbines operating in autonomous mode in Arctic regions. Such type of wind turbine operation is related to fluctuations of the generated power, that negatively affects grid power quality. The increase of wind turbines efficiency is achieved by the utilization of current reserve of power converter, which is a necessary part of megawatts-sized wind energy generation unit. The developed Simulink model of the wind turbines, built according to two of the most suitable for megawatts-level power generation topologies, was used to determine their power output depending on the wind turbine’s rotor speed and the wind speed. Obtained power profile was then used to determine the amount of free current reserve depending on the wind speed, which has verified the ability of both wind turbine topologies to efficiently improve grid power quality, therefore leading to reduction or absence of the necessity to install additional power equipment for the compensation purpose.

In this work, a study was carried out to compare the filtering and hydrodynamic properties of granular filters with solid spherical granules and spherical granules with modifications in the form of micropores. We used the discrete element method (DEM) to construct the geometry of the filters. Models of granular filters with spherical granules with diameters of 3, 4, and 5 mm, and with porosity values of 0.439, 0.466, and 0.477, respectively, were created. The results of the numerical simulation are in good agreement with the experimental data of other authors. We created models of granular filters containing micropores with different porosity values (0.158–0.366) in order to study the micropores’ effect on the aerosol motion. The study showed that micropores contribute to a decrease in hydrodynamic resistance and an increase in particle deposition efficiency. There is also a maximum limiting value of the granule microporosity for a given aerosol particle diameter when a further increase in microporosity leads to a decrease in the deposition efficiency.

Main types of aero-elastic instability for bridges with spans over 100 meters are considered. Methods for investigation of bridge oscillations in a special-purpose experimental facility - the Landscape Wind Tunnel - are described. Examples of tests with elastic similar models of bridges are given, and measurements to mitigate dangerous oscillations early in the bridge design process are described.

The paper examines aerodynamic characteristics of close and parallel automobile and rail bridge arches. Aeroelastic stability of the bridge arches is investigated in a specialized wind-tunnel. It is found that the automobile bridge span is subject to vortex-induced oscillations. These oscillations are reduced by arrangement of a fairing on the bridge-span stiffening girder. Possibility of a buffet- type aerodynamic instability is examined in detail.

In this work, we studied the influence of the internal features of an open cell foam material structure on the efficiency of particle deposition and the pressure drop value of the medium. Constructing of the open cell foam filter models is based on the Distinct Element Method, which allows creating geometry with a random arrangement of pores in space. Calculations of the flow field and particle trajectories were performed using the ANSYS Fluent software package (v. 19.0). Experimental studies were conducted using samples created on the basis of the inverse matrix of 3D printed computational models. Also, models of various geometries with a fixed porosity of the medium are considered. Conducted numerical and experimental studies show that the filter model with the lowest porosity provides the highest deposition efficiency of particles. For a given fixed porosity of the medium, a filter with a change in the cells in diameter across the layers gives a lower value of the pressure drop, which is a significant advantage. The results can serve as the basis for creating aerosol filters with improved characteristics.

In this paper, we consider methods for choosing the effective diameter of solid particles for fluidized bed modeling using the Euler-Euler approach to describing a multiphase medium. Calculations are carried out for the modal average diameter Dmod and average diameter of Sauter D32. Studies have also been conducted for the bidisperse composition of particles, with separation into large and small fractions. The results of numerical simulation were compared with experimental data.

In this paper, we consider methods for selecting effective diameters of solid particles for simulating a fluidized bed using the Eulerian-Eulerian approach in order to describe a multiphase medium. Calculations for modal mean diameter and mean diameter of Sauter were carried out. Studies have also been carried out for the bidisperse composition of the particles, with separation into coarse and fine fraction. The results of the numerical simulation were compared with the data from experimental studies.

The main ideas of the aerodynamic studies of large bridges are presented in present paper. Main types of aero-elastic instability for bridges with spans over 100 meters are considered. A two-step modeling approach is presented. At the first stage, the aerodynamic characteristics of the span fragment are considered, at the second.stage the characteristics of the whole bridge. Methods for investigation of bridge oscillations in a special-purpose experimental facility – the Landscape Wind Tunnel – are described. Examples of tests with elastic similar models of bridges are given, and measurements to mitigate dangerous oscillations early in the bridge design process are described.