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Wyszukujesz frazę "Numerical Simulation" wg kryterium: Temat


Tytuł:
Effect of spiral vanes width on the separation performance of a hydrocyclone
Autorzy:
Liu, Peikun
Wang, Xiaoguo
Jiang, Lanyue
Zhang, Yuekan
Yang, Xinghua
Li, Xiaoyu
Wang, Hui
Powiązania:
https://bibliotekanauki.pl/articles/27323656.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
hydrocyclone
vane width
numerical simulation
separation performance
Opis:
Aiming at the problem of “entrainment fine particles in underflow” of hydrocyclone in grinding and classification process, a hydrocyclone with spiral vanes (the SV hydrocyclone) was proposed. The CFD techniques were used to study the pressure field, velocity field, turbulence field, particle field and classification efficiency of hydrocyclones with spiral vanes of different widths. The results show that the pressure drop, axial velocity, tangential velocity, turbulence intensity of SV hydrocyclone are reduced in different degrees compared with conventional hydrocyclone, and the reduction becomes more obvious with the increase of vane width. In the case of a vane width of 0.04D, the underflow recovery rate of 5μm and 10μm fine particles was reduced by 16.2% and 15.7%. The selection of spiral vanes with small widths is beneficial to improve the separation accuracy of fine particles and reduce the cut particle size.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 6; art. no. 173563
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling and optimization of the YAG:Yb microchip laser passively Q-switched by YAG:Cr absorber
Autorzy:
Buryy, O
Ubizskii, S
Powiązania:
https://bibliotekanauki.pl/articles/175041.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
Yb:YAG crystal
microlaser
Q-switching
numerical simulation
Opis:
Based on analytical and numerical solutions of the rate equations system and the heat conductivity equation, the model of the quasi-three-level passively Q-switched YAG:Yb/YAG:Cr microchip laser is developed. The obtained results are used for its optimization, i.e., for the determination of the output mirror reflectivity, the pumping beam radius, the thickness of the absorber and the phototropic centers concentration maximizing the energy in the laser pulse. The influence of the thermal load on the spatial parameters of the laser beam is also determined.
Źródło:
Optica Applicata; 2014, 44, 4; 621-636
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulations of blast loads from near-field ground explosions in ai
Autorzy:
Dobrociński, S.
Flis, L.
Powiązania:
https://bibliotekanauki.pl/articles/178782.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
near-field
blast load
numerical simulation
high explosive
Opis:
Numerical simulations of air blast loading in the near-field acting on the ground have been performed. A simplified blast model based on empirical blast loading data representing spherical and hemispherical explosive shapes has been simulated. Conwep is an implementation of the empirical blast models presented by Kingery and Bulmash, which is also implemented in the commercial code LS-DYNA based on work done by Rahnders-Pehrson and Bannister. This makes it possible to simulate blast loads acting on structures representing spherical and hemispherical explosive shapes of TNT with reasonable computational effort as an alternative to the SPH and Eulerian model. The CPU time for the simplified blast model is however considerably shorter and may still be useful in time consuming concept studies. Reasonable numerical results using reasonable model sizes can be achieved not only for modelling near-field explosions in air but most areas of geotechnical. Calculation was compared with blast SPH and Eulerian model.
Źródło:
Studia Geotechnica et Mechanica; 2015, 37, 4; 11-17
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study and numerical simulation on fly ash separation with different plate voltages in rotary triboelectrostatic separator
Autorzy:
Zhang, L.
Tao, Y.
Tao, D.
Zhang, W.
Yang, L.
Powiązania:
https://bibliotekanauki.pl/articles/110712.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fly ash
rotary triboelectrostatic separator
plate voltage
numerical simulation
Opis:
As the main solid wastes of coal-fired power plants, fly ash particles with different electrical properties are usually recycled using triboelectrostatic separator. The purpose of this study was to investigate the effect of different plate voltages on the separation of fly ash in a rotary triboelectrostatic separator with experiments and numerical simulation. The maximum values of yield of ash products (48.30%), and decarbonisation rate (50.89%) and the minimum loss-on-ignition (6.61%) were obtained when the plate voltage was 24 kV in the separation experiments, while 55.98%, 59.46%, 5.80% were reached respectively when the plate voltage was 26 kV in the simulation. In general, experimental data were similar with numerical simulation. The turning points appeared around 25 kV due to the increasing mismatch in products, which resulted from the reinforced rebound phenomena, namely the charged particle rebound from the electrode plate with a larger reflection velocity, when the plate voltage increased from 18 to 28 kV. It was validated by the numerical simulation results.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 722-731
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic analysis of a dashpots equipped vibrating screen using finite element method
Autorzy:
Khoshdast, Hamid
Jalilifard, Saeid
Khoshdast, Hami
Powiązania:
https://bibliotekanauki.pl/articles/1448575.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
vibrating screen
dashpots
dynamic characteristic
numerical simulation
FEM modeling
Opis:
Even though vibrating screens have been used in mining industries for over a century, their use has often been cited as challenging in terms of understanding its dynamic responses to different operating factors, particularly those that affect the structural aspects. Among the various aspects of screen design, the control of vibrational energies imposed on various parts of the screen is of particular importance because these vibrations directly affect the separation efficiency and useful life of the screen. This study proposes the use of vibration absorbers to control the adverse effects of severe screen vibrations. The dynamic behavior of a medium-sized vibrating screen utilized in the aggregate industry was investigated using the finite element method for both spring/dashpots and conventional solely spring systems. The modeling process was performed in loaded and unloaded conditions and in three frequencies of 15, 23, and 27 rad/s. Numerical simulation results showed that the use of dashpots can significantly reduce the maximum stress in the screen, such that the maximum stress in the center of gravity of the screen at the optimal frequency of 23 decreased from 237 to about 97 MPa. Also, sieve modal analysis showed that the stress in the sieve equipped with the spring/dashpots system had a more uniform distribution. The results revealed that the use of vibration absorbers can be a promising solution to prevent damage caused by high vibrational energies in screens.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 1; 112-126
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microscale laser shock imprinting of micro-molds with different sizes and shapes
Autorzy:
Yang, H.
Liu, K.
Liu, H.
Powiązania:
https://bibliotekanauki.pl/articles/174650.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
laser shock
imprinting
micro-mold
deformation depth
numerical simulation
Opis:
There are higher requirements for microstructures and high-precision components in microelectronics, photonics, sensors, optoelectronics and medical devices. For changing the traditional manufacturing methods with cumbersome process and complex equipment, researchers put forward a laser shock forming technique which can contribute to the metal forming with high precision and efficiency in recent years. So far, the laser shock forming needed high pulse energy and high energy. In this paper, nanosecond laser with high frequency and low pulse energy was adopted to make possible the aluminum foil forming on the copper micro-molds with different sizes and shapes. The deformations of aluminum foil were measured by SEM, optical profiler and AFM. Also, the deformation laws were analyzed by comparing imprinting results under different micro-molds. Lastly, stress distribution and deformation process of aluminum foil was investigated by numerical simulations.
Źródło:
Optica Applicata; 2018, 48, 4; 671-686
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation of flow field in enhanced gravity concentrator
Autorzy:
Zhu, X.
Tao, Y.
Zhang, L..
Powiązania:
https://bibliotekanauki.pl/articles/110160.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
numerical simulation
enhanced gravity concentrator
three-dimensional velocity
turbulence characteristics
Opis:
Enhanced gravity concentrator have excellent separation accuracy for the fine mineral particles. However, its internal flow characteristics are still in unclear. Therefore, numerical simulation was conducted to study the flow characteristics of concentrator. Effect of centrifugal force and fluidization water pressure on the velocity component of fluid was studied. The simulation accuracy was verified by the theoretical calculation. The turbulence intensity in the radial direction was analyzed to reveal the gradient characteristics. Results show that the three-dimensional velocity has different order of magnitude. The increase of centrifugal force significantly improves the three-dimensional velocity of fluid. However, the fluidization water pressure has little influence on the tangential velocity and axial velocity, but it can effectively improve the radial velocity. High turbulent flow energy and high turbulence dissipation rate are presented in the near wall region, which allows the light particles reentering the separation region. Meanwhile, the fluid presents stable flow pattern in the fall wall region that is conducive to the stratification process. In addition, the increase of centrifugal force increases the turbulence in the near wall region; however, fluidization pressure has no effect.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 975-980
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on self-repairing and non-diffraction of Airy beams in slant atmospheric turbulence
Autorzy:
Li, Y.-Q.
Wang, L.-G.
Powiązania:
https://bibliotekanauki.pl/articles/174867.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
atmospheric turbulence
Airy beam
self-repairing
non-diffraction
numerical simulation
Opis:
The Airy beams propagation in atmospheric turbulence along a slant path was simulated numerically, based on the split-step Fourier method. Also, the self-repairing and non-diffraction characteristics of Airy beams were investigated and compared with beams propagation on a horizontal path. The effects of parameters including zenith angle, propagation distance, radii of Gaussian aperture and turbulence intensity on the two characteristics of beams were revealed. Additionally, the two characteristics of the Airy beam were compared with those of a Bessel–Gauss beam. The results showed that the two beams obscured by Gaussian apertures can be repaired after propagating some distance along a slant path. However, the non-diffraction characteristic of an Airy beam was stronger than that of a Bessel–Gauss beam and the amplitude attenuation rate of the Bessel–Gauss beam was greater than that of the Airy beam in the process of self-repairing. Results obtained can provide a theoretical basis for an outdoor experiment as well as theoretical guidance for various practical applications including laser communications, laser warning systems, and remote sensing.
Źródło:
Optica Applicata; 2018, 48, 3; 435-447
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficiency of ventilated facades in terms of airflow in the air gap
Autorzy:
Schabowicz, Krzysztof
Zawiślak, Łukasz
Staniów, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/1845140.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
ventilated facade
heat transfer
heat transmission
CFD
numerical simulation
energy efficient facade
Opis:
The gradual exploitation of the natural environment has forced most developed countries to promote ecological solutions and the development of sustainable construction. Ventilated facades perfectly match into this trend, and with their appropriate design, they bring real energy savings. This paper analyzes numerically the influence of the inflowing air, mimicking the wind, on the efficiency of heat removal from the ventilated space and heat transmission by thermal radiation and conduction through the consecutive layers of the external wall. For the purpose of comparison, two variants of ventilated facade were adopted: open and closed joints, at different wind speeds prevailing outside. The results obtained show that in windless weather, the ventilated facade with open joints shows higher heat removal efficiency and thus lower heat transmission to the building interior. At higher wind speeds of 5 m/s, the open-joint and closed-joint ventilated facades achieve similar heat transfer efficiency, and the prevailing temperature inside the building for the two technologies is almost identical. Subsequent increments of incoming wind on the building result in minimal differences in the heat transmission to the building interior, representing changes of about 0.1°C at increments of another 5 m/s of incoming wind. Conscious use of this facade technology, along with appropriate urban design of cities, can help reduce the energy needed to cool buildings during the summer period.
Źródło:
Studia Geotechnica et Mechanica; 2021, 43, 3; 224-236
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finite-difference time-domain solution of second-order photoacoustic wave equation
Autorzy:
Rahimzadeh, A.
Chen, S.-L.
Powiązania:
https://bibliotekanauki.pl/articles/173969.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
photoacoustic tomography
numerical simulation
finite-difference time-domain
second-order photoacoustic equation
Opis:
A finite-difference time-domain numerical solution is presented for solving a single second-order photoacoustic equation, instead of solving three coupled first-order equations. In this way, we are able to insert the heating function to the simulation directly instead of initial pressure. Results are validated using k-Wave simulation and show a good agreement for future development. The perfectly matched layer boundary condition has been implemented for a second-order photoacoustic equation and results are compared to Dirichlet, Neumann and Mur boundary conditions.
Źródło:
Optica Applicata; 2016, 46, 3; 435-446
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Usage of modal test in verification of numerical model
Autorzy:
Więckowski, J.
Odyjas, P.
Powiązania:
https://bibliotekanauki.pl/articles/1190011.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
analiza modalna
analiza numeryczna
weryfikacja danych
modal analysis
fans vibrations
numerical simulation
Opis:
Tuning of the numerical model is very important step during designing process. Correctly tuned model ensures proper evaluation of dynamic characteristics of vibrating object. This paper presets comparison of experimental modal analysis and theoretical numerical modal test of axial fan casing. Thanks to properly tuned model, it was possible to receive results of the numerical simulations similar to real test.
Źródło:
Interdisciplinary Journal of Engineering Sciences; 2016, 4, 1; 42--44
2300-5874
Pojawia się w:
Interdisciplinary Journal of Engineering Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finite element method based simulation of electrical breakage of iron-phosphate ore
Autorzy:
Razavian, S. M.
Rezai, B.
Irannajad, M.
Powiązania:
https://bibliotekanauki.pl/articles/110295.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
finite element method
numerical simulation
electrical breakage
iron-phosphate ore
COMSOL Multiphysics
Opis:
In this study, the effect of minerals composition, particle size and shape as well as electrodes distance from iron-phosphate ore samples, was investigated by using a commercial software. Comparison between high voltage pulses and conventional crushing showed that minerals of interest in the electrical comminution product are better liberated than in the conventional comminution. In order to elucidate and confirm the experimental results, numerical simulation of electrical field distributions/intensity were performed. The software uses the finite element method, a numerical technique for calculating approximate solutions of partial differential equations with known boundary conditions. Magnetite, apatite and quartz were the basic minerals of iron-phosphate ore components, and the main material property used in the simulations was electrical permittivity. The results showed that the induced electrical field was strongly dependent on the electrical properties of minerals, the feed particle size and the location of the magnetite mineral (due to higher permittivity) in the ore. The angle of particle contact surface with high voltage electrode was an important factor in the intensity of electrical field. Smaller contact angle resulted in higher intensity of the electrical field. Electrical discharge within the material was converted to electrohydraulic discharge within the surrounding water environment by increasing the distance between the high voltage electrode and the material contact surface.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 1; 137-150
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Slurry shield tunneling in soft ground. Comparison between field data and 3D numerical simulation
Autorzy:
Beghoul, Mohammed
Demagh, Rafik
Powiązania:
https://bibliotekanauki.pl/articles/178799.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
shield tunnelling
soil-structure interaction
3D numerical simulation
back analysis
settlement
Opis:
In urban areas, the control of ground surface settlement is an important issue during shield tunnel-boring machine (TBM) tunneling. These ground movements are affected by many machine control parameters. In this article, a finite difference (FD) model is developed using Itasca FLAC-3D to numerically simulate the whole process of shield TBM tunneling. The model simulates important components of the mechanized excavation process including slurry pressure on the excavation face, shield conicity, installation of segmental lining, grout injection in the annular void, and grout consolidation. The analysis results from the proposed method are compared and discussed in terms of ground movements (both vertical and horizontal) with field measurements data. The results reveal that the proposed 3D simulation is sufficient and can reasonably reproduce all the operations achieved by the TBM. In fact, the results show that the TBM parameters can be controlled to have acceptable levels of surface settlement. In particular, it seems that moderate face pressure can reduce ground movement significantly and, most importantly, can prevent the occurrence of face-expected instability when the shield crosses very weak soil layers. The shield conicity has also an important effect on ground surface settlement, which can be partly compensated by the grout pressure during tail grouting. Finally, the injection pressure at the rear of the shield significantly reduces the vertical displacements at the crown of the tunnel and, therefore, reduces the settlement at the ground surface.
Źródło:
Studia Geotechnica et Mechanica; 2019, 41, 3; 115-128
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of air inlet layout on the inner flow field for a vertical turbo air classifier
Autorzy:
Yu, Yuan
Li, Xingshuai
Zhang, Yu
Jiao, Zhiwei
Liu, Jiaxiang
Powiązania:
https://bibliotekanauki.pl/articles/27323654.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
turbo air classifier
powder technology
air inlet layout
numerical simulation
classification performance
Opis:
In this study, the influence of air inlet layout on the flow field distribution and particle movement trajectory for the vertical turbo air classifier are analyzed comparatively using the numerical simulation method. The air inlet layout adjustment can increase the axial velocity and turbulent dissipation rate at the feeding inlet and do not generate the axial negative velocity, which improves powder material pneumatic transportation and dispersion capacity; the air inlet layout adjustment can match the airflow rotation direction with the rotation direction of the rotor cage, which can eliminate the vortices in the rotor cage channel effectively. Moreover, the particle movement time is shortened and fast classification is completed, which can decrease the particle agglomeration probability and weaken the ‘fish-hook’ effect. The optimization scheme of the air inlet layout is Type-BC. In accordance with the numerical simulation results, the calcium carbonate classification experimental results indicate that the classification performance of the classifier is improved using Type-BC.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 6; art. no. 175859
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation study on NO oxidation by OH radical clusters in flue gas
Autorzy:
Wen, Zhengcheng
Zhang, Xiaofeng
Huang, Ju
Yang, Zhengyin
Powiązania:
https://bibliotekanauki.pl/articles/27323979.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
Fenton reaction
nitric oxide
numerical simulation
reakcja Fentona
tlenek azotu
symulacja numeryczna
Opis:
Fenton reaction is an important method to remove NO from flue gas. • OH radicals generated in the Fenton reaction can effectively oxidize NO to NO2, which is absorbed and removed by alkali sorbent. To supply guidance for engineering research, numerical simulation of NO oxidation by • OH radical clusters in flue gas has been carried out using Fluent software. The average concentration of NO on the cross sections at various positions of a cylindrical pipe with a circular surface was calculated by simulation. Under various working conditions (temperature, • OH/NO molar ratio, NO concentration in flue gas, and jet velocity), NO oxidation efficiency by • OH radical was simulated and the key factors affecting NO oxidation were analyzed. The results show that temperature and • OH/NO molar ratio are the key factors affecting the oxidation of NO by • OH radicals. The injection velocity has also a significant effect on the oxidation efficiency while the moisture and oxygen content are minor factors influencing the process. The optimum oxidation efficiency of NO is obtained at 473–523 K, the molar ratio of • OH/NO ca. 1.4, the jet velocity 10 m/s, and the flue gas velocity of 3 m/s.
Źródło:
Environment Protection Engineering; 2023, 49, 3; 69--82
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł

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