Validation of movement over a belt conveyor drum

This paper presents the use of new modern methods for the research of movement of material on a belt conveyor. One of the innovative methods is Particle Image Velocimetry (PIV), which was used to scan and assess the two-dimensional vector field of speed of particles on the belt conveyor. Outputs from PIV were compared to simulations of the same transport process. These simulations were performed using the Discrete Element Method (DEM). Four transport speeds of material were assessed for a real and simulative belt conveyor model. Software tracking of particle movement was used to determine and compare the trajectories of paths of particles leaving the belt conveyor drum. Validation of the DEM simulation of material movement over a belt conveyor drum using PIV provided acceptable results in the area of particle speed fields. Comparison of the particle path trajectory corresponds to the preliminary hypothesis which leads to calibration of the DEM simulation. The results and assessment of this paper were created based on validation.Web of Science11212411

Use of DEM in the determination of friction parameters on a physical comparative model of a vertical screw conveyor

This article deals with the use of DEM in the application of a screw conveyor for bulk materials. Utilisation of DEM anticipates input parameters which can be obtained only by experimental and laboratory activity in the area of the transport and properties of bulk materials. These concern mainly friction parameters describing flow properties on the transport equipment. Without this knowledge, the use of DEM is limited. With knowledge of the mechanical and physical properties of bulk materials and contact geometries, the use of DEM applies to the simulation of the real behaviour of the conveyed material. This state can only be achieved by verification of the concordance of the simulation and real state, alternatively by calibration. Calibration must be performed on the basis of ranges of input values ascertained in the laboratory environment. After that, it is necessary to obtain the output parameters by an experiment from the DEM-simulation such as particle velocity during transport on the vertical screw conveyor. The same method is used when it is necessary to obtain values from the actual equipment by the PIV method on the basis of which the DEM model will be optimized.Web of Science291342

DEM investigation of the influence of particulate properties and operating conditions on the mixing process in rotary drums: Part 1-Determination of the DEM parameters and calibration process

This paper's goal was to select methods and a calibration procedure which would lead to the determination of relevant parameters of a discrete element method (DEM) and virtual material creation. Seven particulates were selected with respect to their shape (spherical and non-spherical), size and density. The first calibration experiment involved "packing test" to determine the shape accuracy and bulk density of virtual packed particulates. The series of simulations were compared with real experiments, and the size, shape and density of virtual particles were optimized. Using three apparatuses, the input parameter values were experimentally determined for a contact model that defines the behavior of particulates in DEM simulations. The research part of the paper examines the influence of factors such as particle number; pile formation method; and the method of evaluation of the angle of repose on the process of the calibration of virtual material. The most reproducible results were achieved by the "pilling" method and by the rotating drum-both evaluated by the geometric method. However, it is always advisable to make an overall visual comparison of the slope shape between the calibration simulation and the experimental curves. The bowl's diameter to particle size ratio should be greater than 25, and the calibration experiment should contain approximately 4000 particles to ensure representative results during angle of repose calibration experiment.Web of Science82art. no. 22

Simulation of material flow through a sample divider

The prerequisite for a modem approach to innovative procedures of the development of current or even newly created equipment for the transport of particulate materials is the utilization of simulation methods, such as the Discrete Element Method (DEM). This article focuses on the basic, or initial, validation of movement of material through the sample divider. The mechanical-physical properties of brown coal were measured. Based on these parameters the preliminary input values for EDEM Academic were selected, and a simulation of the dividing process was run. The key monitored parameters included density and friction coefficient. Experiments on a realistic model of the equipment were performed and assessed. The total weights of brown coal at the exit from the divider were determined for a specific speed of the divider. The aim of this task was to simulate the realistically determined weight division of the brown coal sample. The result from the DEM was compared with the results of measurement on a realistic model.Web of Science12119919

DEM investigation of the influence of particulate properties and operating conditions on the mixing process in rotary drums: Part 2-Process validation and experimental study

The process of homogenization of particulates is an indispensable part of many industrial processes, and, therefore, it is necessary to pay a special attention to this area and develop it. This paper deals with a complex study of homogenization of particulate matters in a rotary drum in terms of shape, size, and density of particles. In addition, the influence of operating parameters, such as drum filling capacity, rotational speed, and drum filling pattern are also investigated. Studies of reproducibility of discrete element method simulations, effects of rotary drum sizes or effects of drum volumetric filling to the mixture homogeneity index were also carried out. In general, the least satisfactory values of the homogeneity index resulted from the mixing of particles with different densities. The dominating factor of homogenization was the drum filling-up degree. The course of the homogeneity index in 140, 280, and 420 mm drums was very similar and after five revolutions of the drum, identical values of the homogeneity index were achieved for all the drum diameters. The optimal drum filling-up degree is at 40-50% for the spherical particles and 30-40% for the sharp-edged particles. The repeatability of simulations showed the maximum relative standard deviation of the homogeneity index at 0.6% from ten simulation repetitions with the same parametric conditions.Web of Science82art. no. 18

Analysis and optimization of material flow inside the system of rotary coolers and intake pipeline via discrete element method modelling

There is hardly any industry that does not use transport, storage, and processing of particulate solids in its production process. In the past, all device designs were based on empirical relationships or the designer's experience. In the field of particulate solids, however, the discrete element method (DEM) has been increasingly used in recent years. This study shows how this simulation tool can be used in practice. More specifically, in dealing with operating problems with a rotary cooler which ensures the transport and cooling of the hot fly ash generated by combustion in fluidized bed boilers. For the given operating conditions, an analysis of the current cooling design was carried out, consisting of a non-standard intake pipeline, which divides and supplies the material to two rotary coolers. The study revealed shortcomings in both the pipeline design and the cooler design. The material was unevenly dispensed between the two coolers, which combined with the limited transport capacity of the coolers, led to overflowing and congestion of the whole system. Therefore, after visualization of the material flow and export of the necessary data using DEM design measures to mitigate these unwanted phenomena were carried out.Web of Science117art. no. 184

Discrete element method model optimization of cylindrical pellet size

The DEM (Discrete Element Method) is one option for studying the kinematic behaviour of cylindrical pellets. The DEM experiments attempted to optimize the numerical model parameters that affected time and velocity as a cylindrical vessel emptied. This vessel was filled with cylindrical pellets. Optimization was accomplished by changing the coefficient of friction between particles and selecting the length accuracy grade of the sample cylindrical pellets. The initial state was a series of ten vessel-discharge experiments evaluated using PIV (Particle Image Velocimetry). The cylindrical pellet test samples were described according to their length in three accuracy grades. These cylindrical pellet length accuracy grades were subsequently used in the DEM simulations. The article discusses a comparison of the influence of the length accuracy grade of cylindrical pellets on optimal calibration of time and velocity when the cylindrical vessel is emptied. The accuracy grade of cylindrical pellet length in the DEM sample plays a significant role in relation to the complexity of a created simulation.Web of Science72art. no. 10

Experimental grounding of the efficiency of the use of elastic operating elements in the devices for pre-sowing seed treatments

The article is devoted to the experimental studies of the effect of elastic operating elements of a mixer-dresser on seeds. Conducted experimental studies have shown the effectiveness of using the elastic operating elements for pre-sowing seed treatments. The proposed device is intended for the intensification of the process of mixing and dressing, excluding the traumatizing of seeds, and the harmful effect of protectant preparations on maintenance workers, while simplifying and reducing the cost of construction without additional power inputs. Experimental studies have confirmed the hypothesis, that the use ofshells, made of elastic materials,in the function of mixing devices, significantly reduces the time of preparation of homogeneous mixtures, due to the ability to accumulate the potential energy and to transfer it to the granular material,in the form of kinetic energy of mixed particles motion. Based on the performed researches, 3D model of the device for pre-sowing seed treatments has been developed. Hybrid elastic mixer-dressers can be used in agricultural enterprises, dealing with the issues of obtaining multicomponent granular mixtures and seed dressing.Web of Science97S74273

The Effect of Setting the Operating Conditions of the Sampling Device on the Representative Sample of Coal

Currently, emphasis is placed on the efficiency of process technology in the production of energy. Large energy corporations are forced to develop new and optimize existing technologies to reduce emission limits. In coal and biomass combustion technologies, it is important to continually monitor and evaluate the quality of input material. A sampling device is used to obtain a representative sample of the fuel from the continuous conveying process. In this research work, the effect of setting the operating conditions of the rotating sampling device for coal, which is intended for combustion, is investigated. From the operating tests, we found that the different settings of the sampling device (velocity, dimensional parameters) influence the quality and quantity of a representative sample of coal taken from the belt conveyor of the technological line

Monitoring of air tunnels in a cylindrical storage device using ECT tomography

This article focuses on the monitoring of air tunnels in sand, which in common practice are characterised as flow disturbances in the flow of bulk materials inside storage devices, hoppers, silos etc. In this case air tunnels are monitored by the ECT (Electrical Capacitance Tomography) method. The basic principle of the ECT tomographic method is the measurement of permittivity of a measured non-conducting medium. The results gained by an ECT device are then compared with the real, precisely defined measured state. The measured results show that the monitoring of flow disturbances in storage devices using ECT is a new method which does not use optical methods during measurement