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Wyszukujesz frazę "silo flow" wg kryterium: Temat


Tytuł:
Building a numerical model for bulk materials from standard shear test data
Autorzy:
Feise, H.
Daiss, A.
Powiązania:
https://bibliotekanauki.pl/articles/1955777.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
constitutive model
FEM
silo flow material parameters stress
Opis:
While numerical methods have become an integral part of everyday work in process engineering for fluid processes, there is a curious lack of such methods in the field of solid handling. One of the reasons may be the inability of the most often used CFD codes to handle bulk solids. In the paper an attempt is made to show how the behaviour of bulk solids can be modelled using a CFD code without a specific constitutive model for bulk solids. Another reason for not using numerical tools to handle bulk materials is the difficulty of generating the necessary material parameters. Those material models suitable for bulk solids that are available in commercial packages are mostly derived from soil mechanics. Their parameters are determined using a triaxial cell. This device is generally not available in the chemical industries and most often not suitable for bulk solids, due to the high stress levels applied in those tests. In the paper a method is presented which allows the use of standard shear test data, supplemented by data from a compression tests in a "lambda-meter", to determine the parameters of an extended Drucker-Prager model with a compressive yield cap. Model equations are given and parameters are determined for white polymer powder. With these parameters a simulation of silo discharge has been performed successfully using a CFD code. To make CFD codes, which already have the much-needed multi-phase capability, capable of handling bulk solid flow, significant work remains to be done (e.g. shear stresses at rest and anisotropic stress tensors).
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 4; 539-547
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Loads on walls and inserts in a mass-flow silos
Autorzy:
Ding, S.
Wójcik, M.
Jecmenica, M.
Silva de, S. R.
Powiązania:
https://bibliotekanauki.pl/articles/1955779.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
silo flow/loads
insert
Lagrangian-Eulerian
adaptive
fillet
Opis:
A finite element analysis has been carried out to investigate flow patterns and loads on silos either with a ralatively steep hopper, or with a shallow hopper but in the presence of an insert. A Lagrangian-Eulerian approach was first adopted to simulate the material flow pattern, with the precondition that mass flow was obtained. It was then attempted to predict the loads exerted by granular materials on the walls of such silos. The load on the insert was also simulated. Techniques such as the adoption of adaptive meshes and filleting along sharp corners were applied in the analysis to overcome the difficulties usually encountered with large deformations in the FEM and the mathematic singularity presented by the abruptness of geometry. Filleting proved to be necessary to bring down the pressure peak at the transition level. The insert took over a significant part of the loads. Comparison with the classic theories have confirmed that the loads predicted on the wall agree quite well with the theoretical results in the silo's cylinder section, but that differences exist in the hopper section; the difference is greater when the hopper is shallower. It has also shown the limitations of predicting flow patterns of granular materials with the traditional elastic-plastic model; a more advanced model is needed.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 4; 525-538
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Deformation measurements in granular bodies using a Particle Image Velocimetry technique
Autorzy:
Słomiński, C.
Niedostatkiewicz, M.
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/241386.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
PIV
pull-out test
sand
silo flow
strain
wall roughness
Opis:
The paper presents results of strain measurements in cohesionless sand in two different boundary value problems, namely quasi-static pull-out test of a steel wall and confined granular flow in a rectangular model silo using a non-destructive method called Particle Image Velocimetry (PIV) which is a technique for measuring surface displacements from digital images. Advantages and disadvantages of the method are outlined.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2006, 53, 1; 71-94
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
FE-simulations of rapid silo flow with a polar elasto-plastic constitutive model
Autorzy:
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1953957.pdf
Data publikacji:
1998
Wydawca:
Politechnika Gdańska
Tematy:
finite element simulations
polar elasto-plastic constitutive model
silo flow
numerical modelling
model silo
convergent smooth walls
Opis:
The paper presents results on numerical modelling of rapid flow of granular materials in a model silo with convergent smooth walls. The calculations were performed with a finite element method based on a polar elasto-plastic constitutive relation by Muhlhaus (1995). The relation differs from the conventional theory of plasticity by the presence of Cosserat rotations and couple stresses using a mean grain diameter as a characteristic length. The characteristic length causes that numerical results do not depend upon the mesh discretisation. The model tests on rapid silo flow of glass beads performed by Renner in a glass hopper with a large wall inclination from the bottom were numerically simulated. The plane strain FE-calculations were performed by taking into account inertial forces and linear viscous damping. A satisfactory agreement between numerical and experimental results was obtained. Advantages and limitations of a continuum approach for simulations of rapid silo flow were outlined.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 1998, 2, 3; 473-501
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Arching behaviour of cohesive powders in a pilot-scale plane-flow silo
Autorzy:
Berry, R.J.
Birks, A.H.
Bradley, M.S.A.
Powiązania:
https://bibliotekanauki.pl/articles/1955761.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
plane-flow silo
variable geometry hopper
filling condition
arch shape
critical arch dimension
Opis:
The paper records some of the results and observations from a pilot scale plane-flow silo with a variable geometry hopper and a fully width slot outlet. The original objectives were simply to study the shape of arches and their failure mechanisms under a range of conditions. However, the behaviour of arches did not conform to the conventional assumptions and neither did other silo behaviour. The paper contains a summary of the main findings of this work, but concentrates on the arches formed under mass-flow and non-mass-flow geometries for the filling condition.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 4; 479-498
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Review of the "silo quaking" problems in bins of various geometrical shapes and flow patterns
Autorzy:
Roberts, A.
Powiązania:
https://bibliotekanauki.pl/articles/1955767.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
gravity flow
flow pulsations
silo quaking
silo wall loads
Opis:
The paper reviews the characteristics of pulsating or cyclic flow of bulk solids during gravity discharge in bins and silos. The dynamic load phenomenon is often referred to as "silo quaking" and is known to occur in silos of various geometrical shapes, operating under different flow patterns. Examples include mass-flow, funnel-flow, expanded-flow, multi-outlet bins and bins operating under intermediate-flow. While silo quaking is often associated with tall bins, depending on the flow pattern, the problem can also be experienced in bins of squat proportions. The period of pulsations during flow is influenced by various factors, such as, particle size and size distribution, silo wall material and wall roughness, internal friction, moisture content and discharge flow rate. Of particular relevance is the influence of slip-stick effects during shear flow, and velocity at critical sections in the silo during discharge. The paper presents an overview of silo quaking with case studies to illustrate the range of problems that can occur.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 4; 623-641
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulations of flow patterns in silos with a cellular automaton: Part 1
Autorzy:
Kozicki, J.
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1965146.pdf
Data publikacji:
2005
Wydawca:
Politechnika Gdańska
Tematy:
cellular automation
granular flow
flow pattern
insert
silo
Opis:
A simplified cellular automaton was used to calculate the kinematics of non-cohesive granular materials during confined flow in silos. In this model, granular flow was assumed to be an upward propagation of holes through a lattice composed of cells representing single particles. Calculations were carried out with different silo shapes and inserts, transition probabilities, migration rules, outflow schemes, grid types, wall roughness and cell numbers. To visualize the calculation process, horizontal layers of various shades were introduced. The simulation results were compared with laboratory tests in model silos.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2005, 9, 1; 81-102
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The flow of rape seed in a silo equipped with a discharge device
Autorzy:
Kamiński, M.
Antonowicz, R.
Powiązania:
https://bibliotekanauki.pl/articles/1955775.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
silo
anti-dynamic tube
flow rate
pressure distribution
damaged silo
Opis:
The paper contains a review of experiments with rape seed in a model silo with a semicircular flat bottom equipped with a low-height discharge device. Observations of flow patterns were made during filling and discharging through the transparent front wall of the model silo. Measurement of wall normal pressures and discharge flow rate were also made. A properly designed discharging device can eliminate a pressure peak which is usual for the transition point (dynamic overpressure) in mass flow silos. Experiments have shown that a low-height discharge device can be applied to reduce the pressure increase during discharging damaged silos.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 4; 561-569
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Modeling of Wall Pressure in Silo with and Without Insert
Autorzy:
Askif, Frzat
Hammadeh, Hala
Ubysz, Andrzej
Maj, Marek
Powiązania:
https://bibliotekanauki.pl/articles/1845157.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
numerical modeling
silo
silo model
flow pressure
insert
wall pressure
Opis:
This paper presents a methodology based on the finite element method to simulate the flow of granular materials. Moreover, it allows proper estimation of dynamic pressure during silo discharge since this subject is still under discussion, especially for designing silos with an insert (an input element). A 2-D simulation of the discharge process of a cylindrical silo with cone and a central discharging orifice was performed. Two cases were studied, with and without using insert in silo. Numerical analysis was carried out with the help of the uncoupled arbitrary Lagrangian–Eulerian (ALE) approach. The resulting dynamic pressure distribution on the silo wall for each of the two cases was inferred numerically. The resulting values of pressure were compared with the results of the experimental study on a cylindrical metal silo to demonstrate the accuracy of the numerical model in determining the dynamic wall pressure, especially in the case of using an insert in silo during discharge.
Źródło:
Studia Geotechnica et Mechanica; 2021, 43, 1; 22-33
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulations of flow patterns in silos with a cellular automaton: Part 2
Autorzy:
Kozicki, J.
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1965144.pdf
Data publikacji:
2005
Wydawca:
Politechnika Gdańska
Tematy:
cellular automation
collisions
density wave
granular flow
flow pattern
silo
Opis:
An improved cellular automaton has been used to calculate the kinematics of non-cohesive granular materials during confined flow in mass and funnel flow model silos. In this model, based on a gas model of hydrodynamics, collisions and dissipation of particles were taken into account during granular flow. The model allowed for investigations of dilatant zones in granular material during silo flow.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2005, 9, 1; 103-114
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of using insert on the flow pressure in cylindrical silo
Autorzy:
Hammadeh, Hala
Askifi, Farzat
Ubysz, Andrzej
Maj, Marek
Zeno, Amjad
Powiązania:
https://bibliotekanauki.pl/articles/178369.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
silo model
flow pressure
insert
wall pressure
Opis:
This paper presents an experimental investigation of the discharge flow pressure in the vertical silo and the hopper due to the use of insert (top cone with trunk cone bottom). Using the Insert inside the silos is one of the proposed solutions to avoid the problems of having funnel flow pattern, which has a significant effect on the distribution of flow pressure exerted on the silo wall and the hopper. The experiments were performed on a metal cylinder prototype; corn was used as a granular material, and the wall and hopper pressure distribution was measured by a special pressure transducer. The experiments revealed an important result in the flow pressure due to the change in the location of the insert. The experiments were conducted in Damascus University laboratories.
Źródło:
Studia Geotechnica et Mechanica; 2019, 41, 4; 177-183
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of a cellular automata model to granular flow
Autorzy:
Kozicki, J.
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1986936.pdf
Data publikacji:
2002
Wydawca:
Politechnika Gdańska
Tematy:
cellular automata
granular flow
silo
passive state
active state
Opis:
Paper presents the results of simulations of granular flow with a cellular automata model. Flow of granular material behind a moving retaining wall and in a silo with inserts was numerically analysed. Two different migration schemes during flow were assumed. Advantages and limits of the model were outlined.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2002, 6, 3; 429-436
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
FE studies of quasi-static mass flow in bins: the polar elasto-plastic approach
Autorzy:
Tejchman, J.
Powiązania:
https://bibliotekanauki.pl/articles/1955765.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
elasto-plasticity
finite element method
flow
polar approach
silo
Opis:
The paper deals with numerical modelling of confined flow of granular materials in vertical bins. Quasi-static mass flow of non-cohesive sand with a controlled outlet velocity along the entire silo bottom was numerically studied using a finite element method taking into account an elasto-plastic constitutive law laid down within a Cosserat continuum. The influence of the initial density and the mean grain diameter of the solid, wall roughness, wall stiffness and imperfection, the initial stress state and the pressure level on the stress and deformation states in plane-strain vertical bins was investigated. The numerical results were compared with similar model tests performed with a rectangular vertical bin containing sand. The calculated results were in satisfactory agreement with the experimental ones. The advantages and limitations of the polar elasto-plastic approach to model granular silo flow were outlined.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 4; 667-699
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Badania przepływu materiałów sypkich w silosach z urządzeniami odciążającymi w skali modelowej i naturalnej
Testing of the flow of loose materials in silos with load-reducing devices, on model and natural scales
Autorzy:
Antonowicz, R.
Kamiński, M.
Powiązania:
https://bibliotekanauki.pl/articles/160717.pdf
Data publikacji:
2012
Wydawca:
Polski Związek Inżynierów i Techników Budownictwa
Tematy:
silos
materiał sypki
przepływ materiału
urządzenie odciążające
badanie modelowe
badanie in situ
silo
loose material
material flow
flow testing
load reducing device
model test
in situ test
Opis:
W pracy przedstawiono badania przepływu materiałów sypkich w silosach wyposażonych w rurowe urządzenia odciążające. Opisane badania przeprowadzono na modelach i w skali naturalnej. Badania pozwoliły na prawidłowe zaprojektowanie i zrealizowanie urządzeń odciążających w silosach na rzepak minimalizując koszty wzmocnienia osłabionych ścian.
This paper describes tests carried out on the flow of loose materials in silos containing tubular load-reducing devices. The described tests were performed on models and on a natural scale. They enabled the correct design and construction of load-reducing devices in rapeseed silos, minimizing the costs of reinforcing weakened walls
Źródło:
Przegląd Budowlany; 2012, R. 83, nr 4, 4; 100-104
0033-2038
Pojawia się w:
Przegląd Budowlany
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nowa metoda wizualizacji zmian objętościowych podczas przepływu silosowego na podstawie pomiarów z zastosowaniem promieniowania rentgenowskiego. Cz.1
New method of silos flow volume changes visualisation, based on roentgen radiation measurement. Part 1
Autorzy:
Niedostatkiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/162612.pdf
Data publikacji:
2015
Wydawca:
Polski Związek Inżynierów i Techników Budownictwa
Tematy:
silos
przepływ materiału
wizualizacja
metoda pomiaru
stanowisko badawcze
tomografia rentgenowska
silo
material flow
visualization
measurement method
test stand
Roentgen tomography
Opis:
Proces opróżniania silosów charakteryzuje się utrudnieniami i uciążliwościami eksploatacyjnymi, zróżnicowanymi ze względu na konstrukcje silosu, rodzaj składowanego materiału sypkiego oraz sposób opróżniania. W celu rozpoznania mechanizmu płynięcia oraz wpływu parametrów zewnętrznych na zachowanie się materiału sypkiego konieczne jest monitorowanie przepływu za pomocą metod nie wprowadzających zaburzenia w strukturę materiału sypkiego. Do metod takich należy metoda promieniowania rentgenowskiego. W artykule przedstawiono wyniki pomiarów wypływu piasku bezkohezyjnego z modelu silosu z przepływem kominowym. Zastosowanie tomografii rentgenowskiej umożliwiło wizualizację przestrzenna struktury materiału podczas badań.
The process in which the silos storages are being emptied involves many difficulties and operational problems, varied due to the silos structure, type of the stored material and way in which the silo is emptied. In order to recognize the flow patterns and the impact of the external factors on behaviour of the loose material, it is required to monitor the flow with the use of methods that do not change the structure of the loose material. Method based on X-rays is one of the ways to realize the above. The article presents results of measurement of non-cohesive sand, in case of the silo which features funnel flow pattern. Using the X-ray method made it possible to visualize the material structure throughout the research.
Źródło:
Przegląd Budowlany; 2015, R. 86, nr 4, 4; 32-39
0033-2038
Pojawia się w:
Przegląd Budowlany
Dostawca treści:
Biblioteka Nauki
Artykuł

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