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Tytuł:
Application of radiotracers as tools to determine feed flowrate imbalances and particle size segregation in industrial flotation circuits
Autorzy:
Diaz, Francisco
Barrientos, Nelson
Powiązania:
https://bibliotekanauki.pl/articles/24291630.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
radiotracers
flotation
particle size segregation
feed flow distribution
Opis:
This publication presents the application of radiotracers in the characterization of industrial flotation circuits. Two examples are showcased: the detection of feed flow rate imbalances and the characterization of particle size segregation in automatic mineral-cutting machines. The feed pulp distribution was determined from the mean residence times. Particle size segregation was measured by sampling the cutting machines (≅ 25 grams samples) using coarse, intermediate, and fine-sized radiotracer particles. Radiotracers were injected into the feed streams and measured at various points of the circuit using nuclear instruments, allowing for non-invasive and real time detection. Results show that in the rougher flotation stage, the feed flow is distributed almost evenly in lines 2 and 3 (approximately 38% of the flow goes to each line) and to a lesser extent towards line 4 (approximately 24%). In lines 1 and 2 of the scavenger stage, a higher percentage of the flow goes towards line 1 (approximately 59%) and a lower percentage towards line 2 (41%). Line 6 of the rougher flotation is the fastest of the circuit (shortest residence time). In addition, the inlet mineral-cutting machine of the rougher stage segregates particles with a bias for fine sizes (11.4 % more fine-sized particles than coarse ones). This work is an example of how radiotracer technology can be applied to improve metal production and processes. Radiotracers provide reliable information to be used in combination with other metallurgical data to properly assess flotation circuits.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 5; art. no. 174817
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Smart control of energy storage system in residential photovoltaic systems for economic and technical efficiency
Autorzy:
Kaczorowska, Dominika
Rezmer, Jacek
Janik, Przemysław
Sikorski, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/2202548.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
economic efficiency
energy storage system ESS
microgrid management
optimal power flow
OPF
particle swarm optimisation PSO
Opis:
In recent years, due to the increasing number of renewable energy sources, which are characterised by the stochastic nature of the generated power, interest in energy storage has increased. Commercial installations use simple deterministic methods with low economic efficiency. Hence, there is a need for intelligent algorithms that combine technical and economic aspects. Methods based on computational intelligence (CI) could be a solution. The paper presents an algorithm for optimising power flow in microgrids by using computational intelligence methods. This approach ensures technical and economic efficiency by combining multiple aspects in a single objective function with minimal numerical complexity. It is scalable to any industrial or residential microgrid system. The method uses load and generation forecasts at any time horizon and resolution and the actual specifications of the energy storage systems, ensuring that technological constraints are maintained. The paper presents selected calculation results for a typical residential microgrid supplied with a photovoltaic system. The results of the proposed algorithm are compared with the outcomes provided by a deterministic management system. The computational intelligence method allows the objective function to be adjusted to find the optimal balance of economic and technical effects. Initially, the authors tested the invented algorithm for technical effects, minimising the power exchanged with the distribution system. The application of the algorithm resulted in financial losses, €12.78 for the deterministic algorithm and €8.68 for the algorithm using computational intelligence. Thus, in the next step, a control favouring economic goals was checked using the CI algorithm. The case where charging the storage system from the grid was disabled resulted in a financial benefit of €10.02, whereas when the storage system was allowed to charge from the grid, €437.69. Despite the financial benefits, the application of the algorithm resulted in up to 1560 discharge cycles. Thus, a new unconventional case was considered in which technical and economic objectives were combined, leading to an optimum benefit of €255.17 with 560 discharge cycles per year. Further research of the algorithm will focus on the development of a fitness function coupled to the power system model.
Źródło:
Archives of Electrical Engineering; 2023, 72, 1; 81--102
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bödewadt flow and heat transfer of dusty fluid with Navier slip
Autorzy:
Turkyilmazoglu, M.
Powiązania:
https://bibliotekanauki.pl/articles/38694423.pdf
Data publikacji:
2022
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
revolving flow
velocity slip
dusty fluid
wall shears
fluid-particle interaction
heat transfer
Opis:
The current work deals with two-phase flow and heat transfer induced by a mixture of fluid and dust particles revolving with a constant angular velocity above a slippage planar wall. Interaction of the solids with the fluid through an interaction force while rotating above the surface is formulated through a similarity system of equations akin to the Bödewadt flow in the absence of suspended particles. Although the velocity fields of fluid and solid are strictly coupled, the heat fields are decoupled from the velocity fields, but they are still in contact with each other due to the coupling of fluid and particle temperatures. The dusty fluid flow character is simulated numerically to capture the fluid and dust phase behaviors. The momentum and thermal layers are resolved in the presence of wall slip mechanism. Illustrative and quantitative results are eventually presented reflecting the physical features of particles and fluid at any stage of interaction during the rotary motion. It is revealed that the wall slip mechanism can be effective enough to alter the usual Bödewadt flow phenomenon.
Źródło:
Archives of Mechanics; 2022, 74, 2-3; 157-172
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on characteristics of three-dimensional granular meso-reconstruction of coal gangue roadbed
Autorzy:
Fan, Xiang-Xi
Hui, Bing
Ma, Shi-Jie
Fu, Jian-Cun
Zhang, Wen-Jun
Meng, Ling-Xiao
Sun, Zhi
Powiązania:
https://bibliotekanauki.pl/articles/2086979.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
coal gangue roadbed
particle flow
mesoscopic reconstruction
particle breakage
Opis:
The dynamic evolution process of the coal gangue particles’ core retention phenomenon in the process of crushing under stress, the evolution law of grading and the corresponding microscopic mechanical characteristics after continuous particle crushing are analyzed. The meso-level which reveals deformation phenomena of granular materials under the action of external loads is highly complex. At the qualitative level, the static compaction process of coal gangue samples can be roughly divided into three stages: initial compaction stage, compaction and crushing stage, and crushing (compaction) stage. It is proved that the interaction of lateral confined unidirectional compression of granular materials is mainly compression.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 3; 361--374
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustic propagation in inhomogeneous fluids: regularization via the introduction of fine particles
Autorzy:
Jordan, P. M.
Powiązania:
https://bibliotekanauki.pl/articles/38440473.pdf
Data publikacji:
2020
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
inhomogeneous fluids
Laplace transform
particle-laden flow
singular surface theory
Opis:
It is shown, using analytical methodologies, that the velocity field blow-up suffered by vertically ascending acoustic waves in an isothermal atmosphere can be eliminated via the introduction of fine particles. Assuming the inhomogeneous generalization of the particle-laden flow model known as the (linearized) Marble–Thompson model-1, it is established that bounded, exponentially decreasing, shock amplitudes can be obtained provided the mass fraction of particles exceeds a critical value, for which an exact expression is derived. Lastly, supporting numerical results are presented, special cases are discussed, and possible follow-on studies are noted.
Źródło:
Archives of Mechanics; 2020, 72, 1; 59-73
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamics of bubble-particle interaction in different flotation processes and applications - a review of recent studies
Autorzy:
Patnaik, Nelesh
Menon, Aditya
Gupta, Tapesh
Joshi, Vijesh
Powiązania:
https://bibliotekanauki.pl/articles/1450499.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
flotation
bubble-particle interaction
bubble dynamics
multiphase flow
fluid interface
Opis:
Flotation process involves aggregation of the particles based on the material/compound type of random mixtures such as ores and seawater. It is primarily used in pretreatment of water desalination and other industrial applications. The process makes use of various fluid mechanics principles as multifluids are involved. The multi-fluids in most of the flotation processes are of different phases, such as air and water. Like any other process, the efficiency of flotation is important, and hence most of the studies have been dedicated to understanding how the various parameters are affecting the flotation process. Among various parameters, fluids properties and flow parameters chiefly affect the flotation process. In particular, the bubble-particle interaction of the flotation process has been of interest as it is one of the cost-effective ways to enhance flotation efficiency. In this review, the authors present the latest developments in such parametric studies. This paper could be of interest to research students, academic researchers, and practitioners who want to contribute to (or take from) flotation research.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 6; 206-224
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and numerical study on the classification of a cyclonic field in a flotation column
Autorzy:
Li, Xiaoheng
Li, Xiao
Yan, Xiaokang
Wang, Lijun
Zhang, Haijun
Powiązania:
https://bibliotekanauki.pl/articles/109487.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
computational fluid dynamics
cyclonic flow field
cyclonic-static micro-bubble flotation column
particle size distribution
Opis:
The cyclonic-static micro-bubble flotation column (FCSMC) performs well in fine mineral flotation. Compared to traditional flotation columns, its design innovatively introduces a cyclonic structure. The separation of middling and tailing occurs in the cyclonic flow field induced by a cyclonic reversal cone. In this study, the particle size distribution analysis and computational fluid dynamics (CFD) simulations were conducted to reveal the particle distribution law and the classification mechanism in cyclonic flow fields under different circulation pressures. The results showed that particle size showed the same distribution tendency as tangential velocity in the radial direction: both increase from the center and decrease around the wall. As circulation flux increased, the tangential velocity increased, and the particle size differences in the radial direction also increased. The position of the largest particles will move to outside as the largest value of tangential velocity migrates the outward in the radial direction. According to the particle size distribution of the feed, it can be adjusted to the flow field to change the particle distribution, thereby improving the efficiency of separation. This study has an important guiding significance for column design and adjustment of the operating parameters of the flotation process.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 3; 421-431
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of wake structures in bubbly flowsusing Particle Image Velocimetry (PIV)
Autorzy:
Lewandowski, Björn
Fertig, Micha
Krekel, Georg
Ulbricht, Mathias
Powiązania:
https://bibliotekanauki.pl/articles/952673.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bubbly flow
Particle Image Velocimetry
wake analysis
flowcharacteristics
high-speedimaging
przepływ
cząstki
analiza
charakterystyka przepływu
Opis:
The flow structure around rising single air bubbles in water and their characteristics, such as equivalentdiameter, rising velocity and shape, was investigated using Particle Image Velocimetry (PIV) and Shadowgraphy in a transparent apparatus with a volume of 120mL. The effect of different volumetricgas flow rates, ranging from 4μL/min to 2 mL/min on the liquid velocity was studied. Ellipsoidalbubbles were observed with a rising velocity of 0.25–0.29 m/s. It was found that a Kármán vortex streetexisted behind the rising bubbles. Furthermore, the wake region expanded with increasing volumetricgas flow rate as well as the number and size of the vortices.
Źródło:
Chemical and Process Engineering; 2019, 40, 1; 49-55
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cellular particle swarm optimization with a simple adaptive local search strategy for the permutation flow shop scheduling problem
Autorzy:
Seck-Tuoh-Mora, Juan C.
Medina-Marin, Joselito
Martinez-Gomez, Erick S.
Hernandez-Gress, Eva S.
Hernandez-Romero, Norberto
Volpi-Leon, Valeria
Powiązania:
https://bibliotekanauki.pl/articles/230060.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
flow shop
particle swarm optimization (PSO)
local search strategy
hybrid search method
cellular automata
scheduling
Opis:
Permutation flow shop scheduling problem deals with the production planning of a number of jobs processed by a set of machines in the same order. Several metaheuristics have been proposed for minimizing the makespan of this problem. Taking as basis the previous Alternate Two-Phase PSO (ATPPSO) method and the neighborhood concepts of the Cellular PSO algorithm proposed for continuous problems, this paper proposes the improvement of ATPPSO with a simple adaptive local search strategy (called CAPSO-SALS) to enhance its performance. CAPSO-SALS keeps the simplicity of ATPPSO and boosts the local search based on a neighborhood for every solution. Neighbors are produced by interchanges or insertions of jobs which are selected by a linear roulette scheme depending of the makespan of the best personal positions. The performance of CAPSO-SALS is evaluated using the 12 different sets of Taillard’s benchmark problems and then is contrasted with the original and another previous enhancement of the ATPPSO algorithm. Finally, CAPSO-SALS is compared as well with other ten classic and state-of-art metaheuristics, obtaining satisfactory results.
Źródło:
Archives of Control Sciences; 2019, 29, 2; 205-226
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the sedimentation process using flow visualization methods
Autorzy:
Suchecki, Witold
Powiązania:
https://bibliotekanauki.pl/articles/185147.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sedimentation dynamics curve
flow visualization
particle image velocimetry
krzywa dynamiki sedymentacji
wizualizacja przepływu
Opis:
The aim of the paper was to develop determination methods of sedimentation characteristics using PIV image anemometry and suspension image analysis. Two methods of the investigation of sed- imentation process based on visualization techniques were developed. In the first one, using PIV method, vector fields of the velocity of settling particles are determined and then average particle velocities are calculated to establish the so called sedimentation dynamics curve. In the second one, the methods of suspension image analysis are utilized to determine the positions of the upper dis- continuity and to establish the sedimentation curve. Laboratory research on the sedimentation of agalit particles suspended in glycerine was conducted (using PIV method). Additionally, industrial research on the sedimentation of water-absorbing granular material used after the first carbonation (carbonation I) was conducted in a sugar factory (using the second method). The research consisted of photographic registration of images of the settling suspension by means of the time-lapse photog- raphy technique. A laboratory study was conducted for four values of the volume concentration of agalit particles in glycerine (0.5; 1.0; 1.5 and 2.0 vol%). The research methodology, the scope of the conducted measurements and sample research results together with conclusions are presented in this paper.
Źródło:
Chemical and Process Engineering; 2019, 40, 2; 223--233
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multiobjective Improved Particle Swarm Optimisation for Transmission Congestion and Voltage Profile Management using Multilevel UPFC
Autorzy:
Rao, Mallavolu Malleswara
Ramadas, Geetha
Powiązania:
https://bibliotekanauki.pl/articles/1193696.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
congestion
unified power flow controller
improved particle swarm optimization
modular multilevel converter
voltage profile
Opis:
This paper proposes a multiobjective improved particle swarm optimisation (IPSO) for placing and sizing the series modular multilevel converter-based unified power flow controller (MMC-UPFC) FACTS devices to manage the transmission congestion and voltage profile in deregulated electricity markets. The proposed multiobjective IPSO algorithm is perfect for accomplishing the close ideal distributed generation (DG) sizes while conveying smooth assembly qualities contrasted with another existing algorithm. It tends to be reasoned that voltage profile and genuine power misfortunes have generous upgrades along ideal speculation on DGs in both the test frameworks. The proposed system eliminates the congestion and the power system can be easily used to solve complex and non-linear optimisation problems in a real-time manner.
Źródło:
Power Electronics and Drives; 2019, 4, 39; 79-93
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Particle Flow Code modeling of the mechanical behavior of layered rock under uniaxial compression
Modelowanie właściwości mechanicznych skał warstwowych w warunkach ściskania jednoosiowego przy zastosowaniu oprogramowania Particle Flow Code(PFC)
Autorzy:
Yao, Nan
Ye, Yi-Cheng
Hu, Bin
Wang, Wei-Qi
Wang, Qi-Hu
Powiązania:
https://bibliotekanauki.pl/articles/218969.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
skała warstwowa
wytrzymałość na ściskanie jednoosiowe
Particle Flow Code (PFC)
kąt uwarstwienia
mikropęknięcia
layered rock
uniaxial compression test
bedding angle
microcracks
Opis:
In this paper, the different mechanical behaviors of layered rocks with different bedding angles during uniaxial compression tests are studied. Numerical simulation models of layered rock are validated based on laboratory tests, and uniaxial compression tests are conducted by using Particle Flow Code (PFC). Using these simulations, the uniaxial compressive strength, failure patterns, development of micro-cracks, and displacement of meso particles are analyzed. When the bedding angle is similar to the failure angle, the macro failure planes develop directly along the beddings, the bedding behavior dictates the behavior of the layered rock, reducing the compressive strength.
W pracy badano właściwości mechaniczne skał warstwowych zalegających pod różnym kątem uwarstwienia w warunkach ściskania jednoosiowego. Walidację modeli symulacyjnych skał warstwowych przeprowadzono w oparciu o wyniki badań laboratoryjnych, zaś testy ściskania jednoosiowego prowadzono z użyciem pakietu Particle Flow Code (PFC). W oparciu o badania symulacyjne, analizowano wytrzy-małość skał na ściskanie jednoosiowe, modele pękania, powstawanie mikropęknięć i przemieszczenia mezo- cząstek. W przypadku gdy kąt płaszczyzny uwarstwienia ma wartość przybliżoną do kąta pęknięcia, płaszczyzny pękania w skali makro pojawiają się wzdłuż spękań, a układ warstw skalnych determinuje ich wytrzymałość na ściskanie, powodując jej obniżenie.
Źródło:
Archives of Mining Sciences; 2019, 64, 1; 181-196
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation study on strength and failure characteristics of coal-rock composite sample with coal persistent joint
Badanie symulacyjne charakterystyk wytrzymałościowych próbki kompozytowej złożonej z materiału skalnego oraz węgla w którym występują płaszczyzny łupliwości
Autorzy:
Yin, Dawei
Chen, Shaojie
Chen, Bing
Xia, Zhiguo
Powiązania:
https://bibliotekanauki.pl/articles/219275.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
symulacja PFC
próbka kompozytowa złożona z węgla i materiału skalnego
spoistość węgla
charakterystyka wytrzymałościowa
ewolucja mikro-pęknięć
particle flow simulation
coal-rock composite sample
coal persistent joint
strength and failure characteristics
microcrack number evolution
Opis:
Dynamic Mine disasters can be induced by the instability and failure of a composite structure of rock and coal layers during coal mining. Coal seam contains many native defects, severely affecting the instability and failure of the compound structure. In this study, the effects of coal persistent joint on the strength and failure characteristics of coal-rock composite samples were evaluated using PFC2D software. The results show that with the increase of included angle α between the loading direction and joint plane direction, the uniaxial compressive stress (UCS) and peak strain of composite samples first decrease and then gradually increase. The elastic moduli of composite samples do not change obviously with α. The peak strain at α of 45° is the lowest, and the UCS at α of 30° is the smallest. This is inconsistent with theoretical analysis of lowest UCS at α of 45°. This is because that the local stress concentration caused by the motion inconformity of composite samples may increase the average axial stress of upper wall in PFC2D software. Moreover, the coal persistent joint promotes the transformation from the unstable crack expansion to the macro-instability of composite samples, especially at α of 30° and 45°. The majority of failures for composite samples occur within the coal, and no obvious damage is observed in rock. Their failure modes are shear failure crossing or along the coal persistent joint. The failure of composite sample at α of 30° is a mixed failure, including the shear failure along the persistent joint in coal and tensile failure of rock induced by the propagation of coal persistent joint.
Niekorzystne zjawiska dynamiczne w kopalniach mogą być wywołane przez niestabilność i pękanie struktur kompozytowych złożonych z warstw węgla i materiałów skalnych w trakcie eksploatacji górniczej. W złożu węgla ujawnić się mogą liczne defekty wewnętrzne, które w poważnym stopniu rzutują na stabilność i wytrzymałość złożonej struktury. W pracy tej zbadano wpływ spoistości węglu (występowania powierzchni łupliwości) na charakterystykę wytrzymałościową próbki kompozytowej złożonej z węgla i skały z wykorzystaniem oprogramowania PCF 2D. Wyniki symulacji wskazują, że wraz ze wzrostem kąta α pomiędzy kierunkiem działania obciążenia a płaszczyzną łupliwości, jednoosiowe naprężenie ściskające oraz maksymalne odkształcenie próbki kompozytowej w pierwszym etapie zmniejszą się, a następnie zaczną stopniowo wzrastać. Moduł sprężystości próbek kompozytowych nie ulega zmianie wraz ze zmianą kąta α. Maksymalne odkształcenie będzie najmniejsze dla kąta α równego 45°, z kolei jednoosiowe naprężenie ściskające zarejestrowane dla 30° okaże się najniższe. Wyniki te nie wykazują zgodności z wynikami analiz teoretycznych, przewidujących iż najniższe wartości jednoosiowego naprężenia ściskającego powinny wystąpić dla kąta 45°. Dzieje się tak dlatego, że lokalne koncentracje naprężeń wskutek odmienności zachowania poszczególnych składników próbki w trakcie ruchu powodować mogą wzrost średniego naprężenia osiowego ściany górnej, co uwzględnia model z wykorzystaniem oprogramowania PFC 2D. Ponadto, istnienie ciosu i płaszczyzn łupliwości sprawia, że niestabilne i propagujące szczeliny ulegają przekształceniu w makro- niestabilności próbek kompozytowych, zwłaszcza przy kącie α równym 30° i 45°. Większość pęknięć powstających w próbkach kompozytowych występuje w części węglowej, w pozostałych skałach nie notuje się poważniejszych uszkodzeń. Pęknięcia zmęczeniowe w części złożonej z materiału skalnego odbywają się wskutek działania naprężeń ścinających wzdłuż lub w poprzez płaszczyzny łupliwości. Pękanie zmęczeniowe próbki kompozytowej przy kącie α równym 30° jest procesem złożonym, obejmującym pękanie wskutek naprężeń ścinających działających wzdłuż płaszczyzny łupliwości w węglu oraz naprężeń rozciągających działających na część próbki złożoną z materiału skalnego, wskutek propagacji pęknięcia.
Źródło:
Archives of Mining Sciences; 2019, 64, 3; 609-623
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of flow behaviour in a three products hydrocyclone screen: numerical simulation and experimental validation
Autorzy:
Wang, Chuanzhen
Chen, Jianzhong
Shen, Lijuan
Ge, Linhan
Powiązania:
https://bibliotekanauki.pl/articles/109798.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
three productshydrocyclone screen
flow behaviour
Computational Fluid Dynamics
particle image velocimetry
water split
Opis:
A novel three products hydrocyclone screen (TPHS) has been successfully developed; it consists of a cylindrical screen embedded in a conventional hydrocyclone (CH). In the new liquid cyclone, the combination of centrifugal classification and screening was employed for particle separation based on size. The aim of this study is to investigate the flow behaviour in TPHS using numerical simulation and experimental validation. A computational fluid dynamics simulation with a 4.35 million grid scheme and linear pressure–strain RSM generated the economic and grid-independence solution, which agreed well with the experiments of particle image velocimetry and water split. The velocity vector profile reveals that TPHS represented similar flow patterns to CH, wherein in addition to the outer downward swirl flow, inner upward swirl flow, central down-flow, second circulatory flow, and mantle, a particular fluid flow named screen underflow was created in TPHS owing to the presence of a cylindrical screen. The velocity distribution demonstrates that in TPHS, relative to CH, with the increase in radius, the lower tangential and higher radial velocity first increased to a peak and subsequently decreased, while the axial velocity primarily reduced to zero, increased in the opposite direction, and finally decreased rapidly to zero again. In addition, a disadvantageous flow, namely, screen backflow, was generated in TPHS, wherein the farther away the flow is from the feed inlet, the earlier this flow behaviour occurred. However, the rational scheme of aperture size and screen length can completely remove the screen backflow in TPHS.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 4; 879-895
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Potential design improvements of a reverse flow mini-cyclone with a tangential inlet
Autorzy:
Dziubak, T.
Powiązania:
https://bibliotekanauki.pl/articles/185760.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
air filter
mini-cyclones
separation efficiency
separation performance
flow resistance
dust particle size distribution
filtr powietrza
minikomocyklony
skuteczność separacji
wydajność separacji
opór przepływu
rozkład wielkości cząstek pyłu
Opis:
This paper presents an effect of general dimensions of a reverse flow mini-cyclone with a tangential inlet on its separation efficiency. Several mini-cyclone design modifications are presented and evaluated for use in the air filtration systems of motor vehicles. Local design improvements of three components of a reverse flow mini-cyclone with a tangential inlet D-40 of an air filter fitted in an all-terrain vehicle engine were introduced. An asymmetric curvilinear shape of an outlet port was used instead of a symmetrical shape. An outlet vortex finder inlet port shape was streamlined, and a cylindrical outlet vortex finder of the cyclone was replaced with a conical one. Experimental evaluation of the effects of the design improvements of mini-cyclone on its separation efficiency and performance as well as flow resistance was carried out. Separation efficiency of the cyclone was determined using the mass method as a product of dust mass retained by the mini-cyclone and supplied to the mini-cyclone in a specified time. Separation performance of the cyclone was determined as the largest dust particle dz =dzmax in a specific test cycle in the cyclone outlet air stream. A polydisperse PTC-D test dust used in Poland, a substitute for AC-fine test dust was used. Dust concentration at the mini-cyclone inlet was kept at 1 g/m3. The size and total number of dust particles in the air stream at the outlet of the original mini-cyclone and at the outlet of the improved mini-cyclone was determined using a particle counter.
Źródło:
Chemical and Process Engineering; 2018, 39, 1; 15--31
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 44

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