Temat: discrete element method;

Skocz do pozycji: 1.

Tytuł:: Feeder type optimisation for the plain flow discharge process of an underground hopper by discrete element modelling
Autorzy:: Necas, J.
Hlosta, J.
Zurovec, D.
Zidek, M.
Rozbroj, J.
Zegzulka, J.
Tematy:: drag chain conveyor
discrete element method
simulation; Pokaż więcej
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Powiązania:: https://bibliotekanauki.pl/articles/101876.pdf Link otwiera się w nowym oknie
Opis:: This paper describes optimisation of a conveyor from an underground hopper intended for a coal transfer station. The original solution was designed with a chain conveyor encountered operational problems that have limited its continuous operation. The Discrete Element Modeling (DEM) was chosen to optimise the transport. DEM simulations allow device design modifications directly in the 3D CAD model, and then the simulation makes it possible to evaluate whether the adjustment was successful. By simulating the initial state of coal extraction using a chain conveyor, trouble spots were identified that caused operational failures. The main problem has been the increased resistance during removal of material from the underground hopper. Revealed resistances against material movement were not considered in the original design at all. In the next step, structural modifications of problematic nodes were made. For example, the following changes have been made: reduction of storage space or installation of passive elements into the interior of the underground hopper. These modifications made were not effective enough, so the type of the conveyor was changed from a drag chain conveyor to a belt conveyor. The simulation of the material extraction using a belt conveyor showed a significant reduction in resistance parameters while maintaining the required transport performance.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Effect of Aspect Ratio on Iron-Ore Briquettes During Twin-Roll Briquetting
Autorzy:: Kim, Kang-Min
Bae, Jong-Ho
Han, Jeong-Whan
Tematy:: numerical analysis
discrete element method
roll briquetting; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/355616.pdf Link otwiera się w nowym oknie
Opis:: In the ironmaking, sizes of raw materials such as iron ores and coke must be adjusted for subsequent process in the blast furnace. The depletion of high grade iron ore in recent years necessitates a technology that can utilize low-grade fine iron ores. Thus, steelmakers have been studying the sinter-briquette complex firing process that employs a method of charging the sinter feed together with briquettes made of fine iron ore. In this process, larger briquettes increase the briquette productivity per unit time but decrease the green strength of briquettes and they can break during transportation and charging. Thus, the briquette shape is very important. Therefore, in this study, we simulate a twin roll briquetting process using the DEM analysis and compared the compressive force distributions in the briquette for different aspect ratios. This study is a new attempt, because research cases by numerical methods on the same or similar systems are very rare. Consequently, the optimal aspect ratio is 0.5 at briquette height 20 mm, 2.0 at 30 mm, and 1.5 at 40 mm. Also, the average compressive force increased in proportion with the pocket height at the sameaspect ratio. Therefore, to increase the pocket depth for high productivity, the pocket height must also be increased for obtaining high strength briquettes.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Effect of Deflector Plate for Particle Size Segregation Control
Autorzy:: Kim, Kang-Min
Kim, Ju-Hun
Kwon, Jae-Hong
Lee, Ji-A
Han, Jeong-Whan
Tematy:: size segregation
numerical analysis
discrete element method; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/353855.pdf Link otwiera się w nowym oknie
Opis:: In general, uniform mixing of particles is desirable in the process of particle handling. However, during the charging of sinter feed and upper ore, size segregation must be induced to prevent heat imbalance, ensure bed permeability, and prevent the loss of fine ore. In this study, upper ore charging was simulated using a discrete element method (DEM) to find the optimal method for controlling particle size segregation, and the segregation characteristics in the upper ore bed were investigated when a deflector plate was applied to the charging machine. The degree of vertical segregation increased when a deflector plate was applied, and it was confirmed that the segregation direction in the upper ore bed can be controlled by adjusting the charging direction of the upper ore by using a deflector plate. In order to apply this method directly to the actual process, further study is needed to understand the influence of the characteristics of the deflector plate such as length and angle.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Determination of mechanical properties for wood pellets used in DEM simulations
Autorzy:: Gallego, E.
Fuentes, J.M.
Ruiz, A.
Hernandez-Rodrigo, G.
Aguado, P.
Ayuga, F.
Tematy:: biomass
wood pellets
mechanical properties
discrete element method; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Agrofizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2082921.pdf Link otwiera się w nowym oknie
Opis:: Wood pellets are increasingly being used to produce energy as a part of the decarbonization process of the economy, but their handling is associated with several problems, which usually requires that the equipment used has to be modified and improved. The discrete element method is a numerical technique suitable for simulating individual particles and handling systems. This paper focuses on the determination of the mechanical and physical parameters for wood pellet particles which are required to develop a discrete element method model to improve handling and transport systems. This study reports the experimentally determined values for wood pellet particles with respect to particle density, modulus of elasticity, particle – particle and particle – wall coefficients of restitution, and particle – particle and particle – wall coefficients of friction. Following the previous findings by other researchers with large samples of bulk material, it has been found that the modulus of elasticity for individual wood pellets depends on the water content, and the particle – wall coefficient of restitution depends on the impact velocity.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Optimization of a screw conveyors exploitation parameters
Autorzy:: Karwat, Bolesław
Rubacha, Piotr
Stańczyk, Emil
Tematy:: screw conveyor
discrete element method
bulk material
exploitation characteristics; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Powiązania:: https://bibliotekanauki.pl/articles/1841744.pdf Link otwiera się w nowym oknie
Opis:: The paper describes the problem of designing screw conveyors in terms of determining their exploitation characteristics. Based on the actual values of mass efficiency and power demand obtained in a laboratory experiment, the theoretical design methods and the numerical discrete element method model results were verified. The obtained results have shown that the currently used theoretical methods underestimate the mass efficiency and power demand compared to experiments when typical values of filling rate coefficient and progress resistance coefficient are used. It was also shown that the results of DEM simulations are in good agreement with the experiments in terms of mass efficiency and power demand. Based on the exploitation characteristics determined in DEM simulations for different constructions of the screw and different rotational speeds, multi-objective optimization of the exploitation parameters of the screw was performed in order to minimize the power demand of a screw conveyor and simultaneously maximize its mass efficiency. The optimization results showed that it is possible to find such construction and the rotational speed that will maximize the mass efficiency of the conveyor and keep the power demand low, reducing the exploitation costs of the device.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: The vertical screw conveying characteristics of cohesive particle and optimization of design parameters
Autorzy:: Chen, Suifan
Zhang, Xiaomeng
Li, Qipeng
Shen, Ce
Shi, Yongchang
Tematy:: discrete element method
conveying characteristics
NSGA-II
comprehensive evaluation; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Powiązania:: https://bibliotekanauki.pl/articles/24200814.pdf Link otwiera się w nowym oknie
Opis:: The purpose of this paper is to solve the problem of low conveying efficiency and serious blade wear during vertical screw conveying of cohesive particles. Firstly, the reliability of DEM simulation was verified by comparing the simulated and theoretical values and the influence regularity of different design parameters (rotational speed, pitch, and clearance) on screw conveying characteristics were analyzed based on DEM. In addition, the effect of design parameters on the screw conveying characteristics is identified by ANOVA. Then, the multi-objective optimization model with the both of maximizing the average mass flow rate and minimizing the maximum wear depth of the blade was established using the polynomial fitting regression, which was solved by the non-dominated sorting genetic algorithm (NSGA-II). Finally, the comprehensive evaluation was used to determine the best design parameters. The above research results provide a certain reference for the study of cohesive particle’s vertical screw conveying characteristics and equipment optimization design.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Numerical simulations of the exploitation parameters of the rotary feeder
Autorzy:: Karwat, Bolesław
Rubacha, Piotr
Stańczyk, Emil
Tematy:: bulk materials
Discrete Element Method
exploitation characteristics rotary feeder; Pokaż więcej
Wydawca:: STE GROUP
Powiązania:: https://bibliotekanauki.pl/articles/27315596.pdf Link otwiera się w nowym oknie
Opis:: The article presents the problems of determining the mass efficiency of a rotary feeder depending on the selection of design parameters of the device, such as outer diameter, number of blades and rotational speed of the rotor. The hitherto theoretical methods of calculating the feeder efficiency were presented, as well as a new method of determining the device operation parameters was proposed. For this purpose, the numerical Discrete Element Method was used, which allowed simulating the transport of limestone powder in a cell feeder with various design variants. The results of the tests showed that the above design parameters affect the instantaneous efficiency of the feeder and thus impact the distribution of the dosed material during the operation of the device. Depending on the design solution, the simulation results gave information on the fill factor of the feeders. The study showed a significant potential of DEM simulation in the design of circular feeders intended for dosing bulk materials.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: A new approach for obtaining the geometric properties of a granular porous bed based on DEM simulations
Autorzy:: Sobieski, W.
Dudda, W.
Lipiński, S.
Tematy:: granular beds
spatial structure
Discrete Element Method
PathFinder code; Pokaż więcej
Wydawca:: Uniwersytet Warmińsko-Mazurski w Olsztynie
Powiązania:: https://bibliotekanauki.pl/articles/297977.pdf Link otwiera się w nowym oknie
Opis:: In the article, a new way for obtaining a set of geometrical parameters of granular porous beds is presented, if the data on the locations and sizes of all particles is available. The input data were prepared with the use of Discrete Element Method. The other way for acquiring the input data may be the application of Computed Tomography (CT) and Image Analysis (IA) techniques. All geometrical parameters are calculated with the use of own numerical code called PathFinder (freely available in the Internet together with its source code). In addition to description of the method of calculations, two examples of its use are presented. One simulation was performed in PFC3D code, and the other in YADE software. The aim of the article was to show clearly that a porosity is not sufficient to describe the spatial structure of a porous body. In both presented examples, the porosity value is almost the same, but other parameters, e.g. tortuosity, are different. The motivation to write the PathFinder code were significant problems with obtaining geometrical parameters needed in investigations related to granular porous media. The issues described in the article are a part of an overall research methodology relating to the linking the micro- and macro-scale investigations of granular porous beds. The areas of applications of this methodology are not discussed in the article.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Impact of structure parameters on the critical performance of a novel calciner—a DEM-based study
Autorzy:: Zhou, Tiezhuang
Zhang, Fagen
Xu, Run
Gao, Yan
Xie, Genghua
Xiao, Kai
Yang, Bin
Jiang, Wenchun
Tematy:: novel calciner
structure
motion
residence time
discrete element method; Pokaż więcej
Wydawca:: Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Powiązania:: https://bibliotekanauki.pl/articles/59124250.pdf Link otwiera się w nowym oknie
Opis:: Fracture in a revolving tube due to creep deformation and thermal-mechanical fatigue is a growing concern in industrial equipment research and production, especially after long-term exposure to corrosion and high-temperature conditions in roasting furnaces. The calcination temperature and residence time are crucial in the catalyst production process, with optimal conditions en-hancing catalyst activity and stability. To improve the longevity of roasting furnaces, optimizing the construction structure of the calciner is critical. This study develops a novel calciner structure and mathematical models to understand the effect of structural parameters on critical performance. Computer simulations, predictive modelling, and rotational velocity analysis of the novel calciner were performed using a DEM. The effects of the baffle angle and overlap ratio on the flow pattern and MRT were studied through simulations and experiments. The main conclusions are as follows: (1) The operating parameter with the greatest effect on the MRT was the rotational angular velocity, followed by the baffle angle and overlap ratio. (2) The MRT calculation based on the numerical method model showed an error of no more than 10.0% compared to the actual measurement data, confirming the model’s accuracy. Our study provides a theoretical foundation for a deeper understanding of the complex MRT and flow field processes within this novel calciner. It also aids in optimizing the working parameters, performance, and structure of pilot equipment while offering fundamental data for future industrial applications.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Particle shape effect on macroscopic behaviour of underground structures: numerical and experimental study
Autorzy:: Szarf, K.
Combe, G.
Villard, P.
Tematy:: discrete element method
particle shape
underground pipe
digital image correlation; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/178734.pdf Link otwiera się w nowym oknie
Opis:: The mechanical performance of underground flexible structures such as buried pipes or culverts made of plastics depend not only on the properties of the structure, but also on the material surrounding it. Flexible drains can deflect by 30% with the joints staying tight, or even invert. Large deformations of the structure are difficult to model in the framework of Finite Element Method, but straightforward in Discrete Element Methods. Moreover, Discrete Element approach is able to provide information about the grain–grain and grain–structure interactions at the microscale. This paper presents numerical and experimental investigations of flexible buried pipe behaviour with focus placed on load transfer above the buried structure. Numerical modeling was able to reproduce the experimental results. Load repartition was observed, being affected by a number of factors such as particle shape, pipe friction and pipe stiffness.
Dostawca treści:: Biblioteka Nauki

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