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1

Investigation of Dust Transfer Processes During Loading and Unloading Operations Using Software Simulation

Smirnov Y. D., Ivanov A. V.

Journal of Ecological Engineering

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2018

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Vol. 19, nr 4

29--33

EN

In order to limit dust transfer during the operations of material transportation at the factories of the construction industry, factories of the mineral and raw materials complex employ special dust suppression bunkers. These devices are structures located above a railway hopper (either a truck body or a conveyor). Through the input portal of the device, the transported material is transferred. Dusting can also be carried out under the bunkers from the side of the hopper, into which the material is poured. The design of dust suppression bins should be accompanied by a simulation of dust propagation processes. The simulation should be carried out in order to minimize the dust emissions and to select the optimum locations for the dust suppression sprayers.

2

Recording of the Particular Matter Behaviour when Leaving a Container

Vyletelek J., Gelnar D., Zidek M., Zurovec D., Jezerska L.

Inżynieria Mineralna

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2015

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R. 16, nr 2

201--206

EN

The article focuses on behaviour of particular matter depending on marginal conditions with application of the PIV (Particle Image Velocimetry) and DEM (Discrete Element Method). The Discrete Element Method was used for validation of the particular matter behaviour. The research on the bulk material behaviour concentrated on detection of changes of velocity in experimental materials under constant marginal conditions. The marginal condition is an obstacle on the bottom of the storage tank. As experimental material, we selected glass balls of various sizes. The diameter of the particles was 5 and 3 mm. These particles were mixed in a 50/50 proportion up to the capacity of the experimental sample. The output velocity was recorded by a high-speed camera and compared with numerical simulation in the DEM program. The resulting values of the particle velocity in both the PIV and DEM method were compared. The agreement between the experimental outputs and the numerical method in comparison of the flow velocity was on a high level. From results is possible to detect the period when all particles left the tested zone from charts illustrating the average velocity of all particles in the selected areas during drainage of the tank. By comparison of the locations with the period of the flow's termination in the individual zones we can declare that in the course of the flow, the matter leaves the higher delimited zones earlier than zones closer to the outlet hole. The time difference of the mutually successive zones then becomes shorter while approaching the outlet hole. To summarize the whole experiment complexly, we can declare that the particular matter is accelerated towards the outlet hole by action of the 30° incline of the hopper wall. In an area outside the outlet hole, this acceleration occurs especially in the x axis before the matter arrives above the discharge hole, where the core flow is under way and the direction of the matter's acceleration changes from the x axis to the y axis.

PL

W artykule skupiono się na zachowaniu pyłu zawieszonego w zależności od warunków brzegowych z użyciem analizatora obrazu cząstek (ang. skrót PIV – Particle Image Velocimetry) oraz metody elementów dyskretnych (ang. skrót DEM). Metody elementów dyskretnych użyto w celu określenia zachowania pyłu zawieszonego. Badanie materiału sypkiego skupione było na wykryciu zmian w prędkości materiału wysypującego się ze zbiornika, w stałych warunkach brzegowych. Jako materiał eksperymentalny użyto szklane kule o różnych średnicach. Średnice wynosiły 5 oraz 3 mm. Kule wymieszano w proporcji 50/50, aż do osiągnięcia objętości próbki eksperymentalnej. Prędkość wyjściowa została zarejestrowana przez kamerę i porównana z symulacją numeryczną w programie DEM. Porównano uzyskane wyniki określenia prędkości cząstek z obu metod PIV i DEM. Zależność między wynikami eksperymentalnymi i prędkością strumienia wyznaczoną metodą numeryczną była na wysokim poziomie. Dzięki wynikom z wykresów przedstawiających średnią prędkość cząstek na wybranych powierzchniach można określić moment, w którym wszystkie cząstki opuściły badaną przestrzeń. Można stwierdzić, że w przepływ strumienia materiału opuszczającego zbiornik nie jest jednolity. Można stwierdzić, że pył zawieszony przyspiesza w kierunku odbioru, przy 30° kącie nachylenia ściany zbiornika.

3

Investigations on the machine parts treatment by non-bound blast particles

Stotsko Z. A., Stefanovych T. O.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 49, nr 2

440--459

EN

Purpose: of this paper is development of the mathematical models of the methods of treatment by non-bound blast particles. Analysis of non-bound blast particles behavior is carrying out for modeling. The operating factors such as geometrical parameters of a nozzle, distance to the treated surface, and pressure of compressed air and outlet factors such as level of strengthening, depth of hardened layer are determined. It is proposed to put into basis of the mathematical models the energy conception that permits the unification and simplification of mathematical description of the processes. The level of strengthening, and depth of hardened layer are estimated for the plain surfaces by means of created mathematical models. Design/methodology/approach: The main methods used for the theoretical research are mathematical modelling, integral calculus, fundamentals of analytic geometry, probability theory, hydraulics of multiphase flow. The main methods used for the experimental investigations were conducted by receiving diagrams of surface roughness, microhardness of the oblique slices of the treated samples, speckle interferograms of the surfaces treated with the use of non bound blast particles. Findings: Method of mathematical modeling for treatment by non-bound blast particles is developed based on the energy conception. Mathematical model is created that allows calculating the characteristics of surface quality depending on the technological modes of the treatment. Research limitations/implications: It is planned to develop and improve the mathematical models in future research by extending them for the curvilinear treated surfaces, which has movement relative to the nozzle. Practical implications: has the applied software, elaborated on the basis of the models, that allows providing for automation of calculations of the characteristics of surface quality depending on the technological modes of the treatment. Originality/value: It is pioneered receiving functional dependences between the depth of hardening layer, changing of microhardness, degree of hardening and the parameters of equipment, blast, and working medium. Created functional dependences takes into account the distribution of characteristics of working medium (mass and velocity) all along the cross-sections of the blast.

4

Stress distribution in the material and development of loads on the wall during hopper filling

Ding S., Enstad G. G.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2003

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Vol. 7, No 4

513-524

EN

Stress distributions developing in granular materials in hoppers during the process of filling is fundamental for an understanding of the phenomena observed in hoppers. Predictions of such stress distributions are therefore essential. In this paper, based on a model which was created to simulate various filling procedures, an (ABAQUS) analysis has been carried out to investigate the development of stress distribution in the material and the loads on the hopper wall when the hopper is filled by the concentric-filling method. Calculations have been carried out either according to a procedure known as "switch-on" or according to the so-called layer-by-layer procedure. It was found that the maximum stress developed at the end of the filling, not at the bottom, but somewhere in the lower area of the hopper (layer 3). The stresses developed during layer-by-layer filling were greater than those developed during the switch-on filling in the lower area of the hopper, but were smaller in its upper area. Maxima of normal pressure along the wall were not at the outlet, even from the very beginning of filling. Instead, it was located at a position around 2/5 of the length of the wall from the outlet when the filling was finished. Various filling methods would have an effect on the stress distribution within the material and, consequently, affect the type and magnitude of loads on the hopper wall, and particularly at the hopper outlet.