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Wyświetlanie 1-13 z 13
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:
Period verification device for ventilation rate standard rods based on a digital thermal flowmeter
Autorzy:
Hu, Jiacheng
Sha, Ying
Cai, Jinhui
Liu, Ying
Liu, Suijun
Powiązania:
https://bibliotekanauki.pl/articles/2052108.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ventilation rate standard rod
period verification
numerical simulation
digital thermal flowmeter
micro-pressure difference adjustment
Opis:
Ventilation rate is a physical index that is strictly controlled during cigarette manufacturing because an abnormal ventilation rate can affect the release of mainstream smoke, tar, and other components harmful to human health. Therefore, the standard rod is used for measuring the ventilation rate, which necessitates accurate and effective periodic inspections. In this study, we designed and built a set of special tobacco ventilation rate standard rods to assess the standard device during its verification period and used a digital thermal flowmeter as the flow standard.We determined the micro-pressure adjustment interval through fluid simulation, and conducted an experimental verification based on the simulation results. At the adjustment point where the differential pressure value was 0 Pa, the period verification device was tested under the standard values of 27.38%, 58.83%, and 71.95%. The results show that the measurement errors of the device are -0.42%, 0.55%, and -0.13% respectively, which all meet the verification regulation requirements and indicate that the device is applicable in practical situations.
Źródło:
Metrology and Measurement Systems; 2022, 29, 1; 231-244
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical modeling of large floating roof reservoir temperature arena
Autorzy:
Liu, Y.
Fan, J.
Cheng, Q.
Powiązania:
https://bibliotekanauki.pl/articles/778000.pdf
Data publikacji:
2018
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
floating roof tank
temperature field
natural convection
numerical simulation
Opis:
The current study is a simplification of related components of large floating roof tank and modeling for three dimensional temperature field of large floating roof tank. The heat transfer involves its transfer between the hot fluid in the oil tank, between the hot fluid and the tank wall and between the tank wall and the external environment. The mathematical model of heat transfer and flow of oil in the tank simulates the temperature field of oil in tank. Oil temperature field of large floating roof tank is obtained by numerical simulation, map the curve of central temperature dynamics with time and analyze axial and radial temperature of storage tank. It determines the distribution of low temperature storage tank location based on the thickness of the reservoir temperature. Finally, it compared the calculated results and the field test data; eventually validated the calculated results based on the experimental results.
Źródło:
Polish Journal of Chemical Technology; 2018, 20, 1; 67-74
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical investigation of the inner flow in a centrifugal pump at the shut-off condition
Autorzy:
Liu, H.
Wu, X
Tan, M.
Powiązania:
https://bibliotekanauki.pl/articles/281524.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
centrifugal pump
numerical simulation
shut-off condition
PIV
Opis:
The unsteady flow fields in a centrifugal pump at the shut-off condition (SOC) are simulated by the Unsteady Reynolds Averaged Navier-Stokes (URANS) approach. To improve simulation accuracy and assign the boundary condition, special 3D models are made. Three-dimensional URANS equations are solved on high-quality unstructured grids with the shear stress transport turbulence model by using the computational fluid dynamics (CFD) code CFX-11.0. Furthermore, the numerical simulation results are validated by particle image velocimetry (PIV) measurements. The main goal of the study is, on one hand, the validation of the numerical procedure proposed, and on the other hand, the detailed analysis of the unsteady inner flow field distribution and pressure fluctuation in the centrifugal pump at SOC. In addition, the head of the pump at SOC is predicted based on CFD results. The flow analysis indicates that there exists two eddies in each impeller flow passage, and the velocity at the volute diffusion part is very low. The amplitudes of pressure fluctuation at ƒr (impeller rotation frequency) and 3ƒr dominate in the impeller, while the pressure fluctuation at ƒb (blade passing frequency) is dominant in the volute.
Źródło:
Journal of Theoretical and Applied Mechanics; 2013, 51, 3; 649-660
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
3-D simulation of vertical-axial tidal current turbine
Autorzy:
Zhang, Z.
Ma, Y.
Jiang, J.
Liu, W.
Ma, Q.
Powiązania:
https://bibliotekanauki.pl/articles/260421.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
tidal current energy
vertical-axial turbine
hydrodynamic performance
CFD
numerical simulation
3-D effect
Opis:
Vertical-axial tidal current turbine is the key for the energy converter, which has the advantages of simple structure, adaptability to flow and uncomplex convection device. It has become the hot point for research and application recently. At present, the study on the hydrodynamic performance of vertical-axial tidal current turbine is almost on 2-D numerical simulation, without the consideration of 3-D effect. CFD (Computational Fluid Dynamics) method and blade optimal control technique are used to improve accuracy in the prediction of tidal current turbine hydrodynamic performance. Numerical simulation of vertical-axial tidal current turbine is validated. Fixed and variable deflection angle turbine are comparatively studied to analysis the influence of 3-D effect and the character of fluid field and pressure field. The method, put the plate on the end of blade, of reduce the energy loss caused by 3-D effect is proposed. The 3-D CFD numerical model of vertical-axial tidal current turbine hydrodynamic performance in this study may provide theoretical, methodical and technical reference for the optimal design of turbine.
Źródło:
Polish Maritime Research; 2016, 4; 73-83
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
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:
Simulation of Dendrite Morphology and Micro-Segregation in U-Nb Alloy During Solidification
Autorzy:
Su, Bin
Liu, Jing-Yuan
Zhang, Xiao-Peng
Yan, Xue-Wei
Powiązania:
https://bibliotekanauki.pl/articles/2174585.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
U-Nb alloys
solidification process
dendrite growth
cellular automaton
numerical simulation
Opis:
Due to the importance of uranium and uranium alloys to national defence and nuclear industrial applications, it is necessary to understand dendrite formation in their solidification structures and to control their microstructures. In this study, a modified cellular automaton model was developed to predict 2-D and 3-D equiaxed dendrite growth in U-Nb alloys. The model takes into account solute diffusion, preferential growth orientation, interface curvature, etc., and the solid fraction increment is calculated using the local level rule method. Using this model, 2-D large-scale and 3-D equiaxed dendrite growth with various crystallographic orientations in the U-5.5Nb alloy were simulated, and the Nb micro-segregation behaviour during solidification was analysed. The simulated results showed reasonable agreement with the as-cast microstructure observed experimentally.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 4; 1333--1339
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
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:
Water-exit process modeling and added-mass calculation of the submarine-launched missile
Autorzy:
Yang, J.
Feng, J.
Li, Y.
Liu, A.
Hu, J.
Ma, Z.
Powiązania:
https://bibliotekanauki.pl/articles/260251.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
submarine-launched missile
fluid-structure interaction
water-exit dynamic model
time-varying added-mass
numerical simulation
Opis:
In the process that the submarine-launched missile exits the water, there is the complex fluid solid coupling phenomenon. Therefore, it is difficult to establish the accurate water-exit dynamic model. In the paper, according to the characteristics of the water-exit motion, based on the traditional method of added mass, considering the added mass changing rate, the water-exit dynamic model is established. And with help of the CFX fluid simulation software, a new calculation method of the added mass that is suit for submarine-launched missile is proposed, which can effectively solve the problem of fluid solid coupling in modeling process. Then by the new calculation method, the change law of the added mass in water-exit process of the missile is obtained. In simulated analysis, for the water-exit process of the missile, by comparing the results of the numerical simulation and the calculation of theoretical model, the effectiveness of the new added mass calculation method and the accuracy of the water-exit dynamic model that considers the added mass changing rate are verified.
Źródło:
Polish Maritime Research; 2017, S 3; 152-164
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study on the dynamic tensile mechanical properties of marble under water and oil conditions
Autorzy:
Li, Chaoxin
Liu, Dongyan
Zhu, Yunhui
Powiązania:
https://bibliotekanauki.pl/articles/27312136.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
rozciąganie dynamiczne
pręt Hopkinsona
rozpraszanie energii
symulacja numeryczna
marmur
woda
olej
dynamic tensile
Hopkinson bar
energy dissipation
numerical simulation
marble
water
oil
Opis:
To investigate the dynamic tensile properties and energy dissipation characteristics of marble in three different conditions: dry, water-saturated, and oil-saturated, a Brazilian disk splitting test was conducted using a 50 mm diameter Hopkinson pressure bar (SHPB) device. The findings indicate that the peak strain and dynamic tensile strength of the three conditions increase with strain rate, exhibiting a clear strain rate effect. Additionally, lubricating effects of water and oil weaken internal shear sliding friction, thus promoting crack expansion. Furthermore, immersion of fluid in marble weakens the cementation of internal mineral particles, leading to lower tensile strength of marble saturated with water and oil compared to dry marble under dynamic impact. When analyzing the energy dissipation of marble, both the absorption energy and dissipation energy density increase with oil strain rate, indicating a positive correlation. Moreover, numerical results obtained from ANSYS/LS-DYNA correspond well with experimental data, thus verifying and interpreting the experimental outcomes.
Źródło:
Archives of Civil Engineering; 2023, 69, 3; 317--330
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Temperature Field, Heat and Fluid Flow of Two-Phase Zone Continuous Casting Cu–Sn Alloy Wire
Autorzy:
Luo, J.
Liu, X.
Wang, X.
Powiązania:
https://bibliotekanauki.pl/articles/380230.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
continuous casting
two-phase zone continuous casting
alloy Cu-Sn
numerical simulation
temperature field
heat flow
fluid flow
odlewanie ciągłe
strefa odlewania dwufazowego
stop Cu-Sn
symulacja numeryczna
pole temperatury
przepływ ciepła
przepływ płynu
Opis:
Cu–4.7 wt. % Sn alloy wire with Ø10 mm was prepared by two-phase zone continuous casting technology, and the temperature field, heat and fluid flow were investigated by the numerical simulated method. As the melting temperature, mold temperature, continuous casting speed and cooling water temperature is 1200°C, 1040°C, 20 mm/min and 18°C, respectively, the alloy temperature in the mold is in the range of 720°C–1081°C, and the solid/liquid interface is in the mold. In the center of the mold, the heat flow direction is vertically downward. At the upper wall of the mold, the heat flow direction is obliquely downward and deflects toward the mold, and at the lower wall of the mold, the heat flow deflects toward the alloy. There is a complex circular flow in the mold. Liquid alloy flows downward along the wall of the mold and flows upward in the center.
Źródło:
Archives of Foundry Engineering; 2016, 16, 1; 33-40
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three-dimensional simulation of the fracture system distribution in formation rock based on fractal method
Trójwymiarowe symulacje rozkładu spękań w skałach z wykorzystaniem metody fraktali
Autorzy:
Li, W.
Zhao, H.
Liu, M.
Li, S.
Sun, W.
Wang, L.
Powiązania:
https://bibliotekanauki.pl/articles/219509.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
szczelinowanie hydrauliczne
wymiary fraktali
naturalne spękania
spękania powstałe wskutek szczelinowania
symulacje numeryczne
hydraulic fracturing
fractal dimension
natural fracture
fracturing fracture
numerical simulation
Opis:
During exploitation process of fractured reservoir, the complex distribution of natural fracture system may lead to a series of accidents, such as sand plug and multi fracture extension in hydraulic fracturing operation. Considering the difficulties of numerical analysis on formation rock mass fracture system distribution, three-dimensional geometry model of a single fracture formation is proposed in this paper, and fractal geometry method is introduced to build the three-dimensional fractal description model of formation fracture system distribution. On this basis, the effects of fractal parameters on natural fracture porosity, permeability and other properties are analyzed. The results show that: First, the number and propagation of natural fracture are controlled by the fractal dimension, the number of groups and the initial quantity. Second, the fractal dimension of natural fracture distribution has an obvious effect on natural fracture porosity and permeability. Third, porosity and permeability of natural fracture distribution both experience exponential growth as fractal dimension increases. Fourth, when the fractal dimension remains constant, the porosity and permeability of natural fractures both increase with the fracture scale.
W trakcie eksploatacji złoża zalęgającego w spękanych warstwach i pokładach złożony system naturalnych spękań prowadzić może do licznych incydentów, np. powstawania zatorów piaskowych lub nadmiernego rozszerzenia spękań w trakcie szczelinowania hydraulicznego. Z uwagi na trudności związane z analizą numeryczną rozkładu spękań skał macierzystych, w pracy zaproponowano trójwymiarowy model geometryczny pojedynczego pęknięcia z wykorzystaniem metod geometrii fraktalnej do opracowania trójwymiarowego modelu opisującego powstawanie układu spękań i ich rozkład. Na tej podstawie przeanalizowano wpływ parametrów fraktalnych na naturalną porowatość pękniętych skał, ich przepuszczalność oraz pozostałe właściwości. Wyniki badań wskazują że, po pierwsze, liczba i tempo propagacji naturalnych spękań uzależnione są od wymiarów fraktalnych, liczby grup i wielkości początkowej. Po drugie, wymiary fraktalne naturalnego systemu spękań skał mają zdecydowany wpływ na porowatość i przepuszczalność. Po trzecie, porowatość i przepuszczalność naturalnych systemów pęknięć wykazują wzrost w miarę wzrastania wymiarów fraktalnych. Po czwarte, gdy wymiary fraktalne pozostają niezmienne, zarówno porowatość i przepuszczalność naturalnych spękań rosną wraz ze skalą fraktali.
Źródło:
Archives of Mining Sciences; 2018, 63, 2; 425-436
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Studies on a Three-dimensional Flow Field in Four-Roller Compact Spinning with a Guiding Device
Badania numeryczne trójwymiarowego pola przepływu w czterowałkowym aparacie rozciągowym przędzarki kompaktowej wyposażonej w urządzenie prowadzące
Autorzy:
Liu, X.
Xie, C.
Su, X.
Mei, H.
Powiązania:
https://bibliotekanauki.pl/articles/233593.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
four-roller compact spinning
guiding device
3D flow field
numerical simulation
fluent
kompaktowy układ czterorolkowy
urządzenie prowadzące
pole przepływu 3D
symulacja numeryczna
analiza pola przepływu
Opis:
Research on the flow field in the fibre-converging zone is always the emphasis and difficulty of compact spinning. Therefore in this work numerical studies on the three-dimensional flow field in four-roller compact spinning with a guiding device were carried out using Fluent software. First a three-dimensional physical model of the fibre-converging zone was obtained using AutoCAD software. Then numerical simulations of the three-dimensional flow field in four-roller compact spinning with and without a guiding device were presented, respectively, using Fluent software. It was shown that the negative pressure is chiefly concentrated near the air-suction flume, and the velocity reaches the maximum on the centre line. Comparing with the flow field in compact spinning without a guiding device, the effective range of negative pressure in four-roller compact spinning with a guiding device increases significantly and negative pressure use efficiency improves accordingly. Furthermore the optimal installation position of the guiding device was studied, and it was shown that the optimal installation position is closely related to the linear density of the spun yarn. Finally the theoretical results obtained were illustrated by experiments.
Podstawową trudnością w przędzeniu kompaktowym jest analiza pola przepływu strumienia włókien, którą przeprowadzono korzystając ze specjalnego oprogramowania – Fluent Software. Wstępnie opracowano model fizyczny procesu korzystając z systemu AutoCAD. Wykazano, że podciśnienie jest głównie skoncentrowane w pobliżu kanałów zasysających i prędkość osiąga swoje maksimum w centrum układu. Wykazano korzyści z zastosowania układu czterorolkowego w porównaniu do układu klasycznego i optymalne pozycje rozmieszczenia ściśle uzależnione od masy liniowej produkowanej przędzy. Uzyskane obliczenia teoretyczne porównano z wynikami praktycznymi.
Źródło:
Fibres & Textiles in Eastern Europe; 2013, 6 (102); 50-57
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-13 z 13

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