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Tytuł:
Investigation into the growgth directions of a ductile crack under tensile loading
Autorzy:
Zhang, Xiao--Bing
Li, Jia
Recho, N.
Powiązania:
https://bibliotekanauki.pl/articles/279697.pdf
Data publikacji:
1999
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
fracture
full elastic--plastic field
crack propagation criteria
Opis:
In this paper, we use an energy variational methodto study the full stress field near a stationary crack in a plane state in a power--law hardening material under mode I liading. Associated with the finite element method the trejectory line fields of the principal stresses and the maximum shear stresses have been drawn in order to determine the crack growth direction. It appears that the crack can propagate along a cleavage band or along a slip band according to the triaxial tensile stress level in the vicnity of the crack. The growth direction of a ductile crack depends on the competition between the stress concentractions along these bands.
W pracy zastosowano metodę wariacji energii do badania pełnego pola naprężeń wokół stacjonarnego pęknięcia w płaski stanie odkształcenia dla materiału o potęgowym wzmocnieniu dla I typu obciążenia. Przy pomocy metody elementów skończonych wyznaczono pola trajektorii naprężeń głównych i maksymalnych naprężeń ścinających w celu określenia kierunku wzrostu szczeliny. Stwierdzono, iż pęknięcie rozwija się wzdłuż pasm rozdzielczości lub pasm ścinania, zgodnie z poziomem trójosiowych naprężeń rozciągających w otoczeniu pęknięcia. Kierunek wzrostu pęknięcia ciągliwego zależy od relacji pomiędzy koncentracjami naprężeń wzdłuż tych pasm.
Źródło:
Journal of Theoretical and Applied Mechanics; 1999, 4; 779-789
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface modification of fly ash spheroidal particles and their application in the adsorption of phosphorus and chromium(VI) from single and competitive solute systems
Autorzy:
Chen, Chen
Cheng, Ting
Zhang, Xiao
Zhang, Minte
Lv, Ruiyang
Powiązania:
https://bibliotekanauki.pl/articles/2032957.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fly ash
Langmuir isotherm
adsorption phosphorus
popiół lotny
izoterma Langmuira
adsorpcja fosforu
Opis:
This work focuses on the surface modification of fly ash spheroidal particles and their application in phosphorus and chromium(VI) adsorption. The results show that through surface modification, amorphous silica-alumina gels precipitated on the spheroidal particle surface (by which the microsurface area of the reaction products is effectively enlarged) and the surface zeta potential was changed to fit for adsorbing anions. During the adsorption experiment (single and competitive solute systems), chromium(VI) was easier to adsorb. The surface zeta potential and the existence of competitive ions should be recognized as two important factors affecting adsorption efficiency. A higher temperature could improve the adsorption efficiencies of the two solute systems. The fitting results of the pseudo-second-order model (single and competitive solute systems) show better agreement than those of the pseudo-first-order model at every temperature. The Langmuir adsorption isotherm equation can better simulate the adsorption process in single solute sy039stems, but only the chromium(VI) adsorption process can be fitted by the competitive Langmuir adsorption isotherm in competitive solute systems.
Źródło:
Environment Protection Engineering; 2020, 46, 3; 39-59
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positronium time-of-flight Measurements of Mesoporous Silica Films
Autorzy:
Kuang, Peng
Zhang, Xiao
He, Chun
Cao, Xing
Wang, Bao
Powiązania:
https://bibliotekanauki.pl/articles/1029796.pdf
Data publikacji:
2018-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
61.05.-a
68.47.Mn
Opis:
Mesoporous silica films were synthesized with various concentrations of cetyltrimethylammonium bromide (CTAB) in precursor sols through the method of electro-assisted self-assembly (EASA). Oriented pore channels were observed in the films prepared with more CTAB in the precursor sols. Positronium time-of-flight (Ps-TOF) measurements were performed for the silica films with different porous structures. It is demonstrated that the Ps emission intensity and energies are well correlated to the apparent porosity, pore interconnectivity and possibly pore channel orientation. The results indicate that Ps-TOF can be a useful technique for probing the structures of porous films.
Źródło:
Acta Physica Polonica A; 2018, 133, 1; 3-6
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
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:
Optimization analysis of construction scheme for large-span highway tunnel under complex conditions
Autorzy:
Pengfei, Jiao
Zhang, Xiao
Li, Xinzhi
Jiang, Bei
Liu, Bohong
Zhang, Haojie
Powiązania:
https://bibliotekanauki.pl/articles/231477.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
materiał podobny
tunel o dużej rozpiętości
metoda centralnego schematu krzyżowego
metoda podwójnego dryfu
ściana boczna
similar material
large-span tunnel
center cross-diagram method
double drift method
sidewall
Opis:
The construction process of the tunnel ground deformation regularity of surrounding rock, stability, deformation control of tunnel surface based on the requirements, combined with the characteristics of shallow tunnel with large-span. Used three-dimensional numerical simulation software, established a dynamic tunnel analysis program to simulate the construction process of center cross-diagram method and double sidewall drift method. Based on the stratum deformation, supporting force and analysis of plastic zone distribution, comparative analysis of engineering adaptability of different construction methods from the construction process and construction mechanics, get optimization tunnel construction scheme.
Źródło:
Archives of Civil Engineering; 2018, 64, 4/I; 55-68
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A spatial study on Keshan disease prevalence and selenoprotein P in the Heilongjiang Province, China
Autorzy:
Wang, Yanan
Zhang, Xiao
Wang, Tong
Hou, Jie
Guo, Zhongying
Han, Xiaomin
Zhou, Huihui
Liang, Hong
Xing, Zhifeng
Powiązania:
https://bibliotekanauki.pl/articles/2095499.pdf
Data publikacji:
2021-09-03
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
prevalence
biomarker
prevention and control
endemic cardiomyopathy
selenoprotein P
spatial regression analysis
Opis:
ObjectivesFew spatial studies on Keshan disease (KD) prevalence and serum selenoprotein P (SELENOP) levels have been reported in the Heilongjiang Province, China. This study aimed to investigate the spatial relationships between KD prevalence, SELENOP levels, and the socio-economic status for the precise prevention and control of KD.Material and MethodsThe study was carried out in all the 66 KD endemic counties in the Heilongjiang Province using a non-probability sampling method of a key village survey based on county-wide case-searching. The participants completed a questionnaire and had their serum SELENOP levels measured using enzyme-linked immunosorbent assay. Thematic maps were created, and spatial regression analysis was performed by ordinary least squares using ArcGIS 9.0.ResultsOverall, 53 676 residents were surveyed based on case-searching, and blood samples were collected from 409 residents. In total, 50 chronic KD cases were identified with a total prevalence of 9.3/10 000 population. The prevalence in the Tangyuan County was the highest (250/10 000 population). The mean serum SELENOP level was 13.96 mg/l. The spatial regression analysis showed that KD prevalence positively correlated with SELENOP levels and negatively with per capita disposable income among rural residents.ConclusionsThe Tangyuan County should be considered for the precise prevention and control of KD. Further research is necessary to verify the reliability of SELENOP for estimating body selenium levels, and to better understand the relationship between selenium intake and KD in the investigated area.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2021, 34, 5; 659-666
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Propagation of solitary wave in non-uniform fiber system with high-order nonlinear effects
Autorzy:
Xiao, Y.
Zhang, J.
Zhang, L.
Powiązania:
https://bibliotekanauki.pl/articles/173308.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
solitary wave
coupled higher-order nonlinear Schrödinger equation
high-order nonlinear effect
Opis:
The ultra-short pulse propagation in a non-uniform fiber system is investigated based on the variable coefficient coupled higher-order nonlinear Schrödinger equation with the dispersion gain and nonlinear gain terms. By using the ansatz method and the split-step Fourier method, we get the exact solitary wave solution, with which the transmission process of the solitary wave is studied. Furthermore we obtain the stability of the solitary wave under finite initial perturbations. The interaction between two neighboring solitary waves is also studied.
Źródło:
Optica Applicata; 2018, 48, 2; 273-284
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transmission stability of chirped dark vector quasi-solitons in birefringent fiber system with nonlinear gain
Autorzy:
Xiao, Yan
Zhang, Jing
He, Qi
Powiązania:
https://bibliotekanauki.pl/articles/1835764.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
chirped dark vector quasi-soliton
coupled Ginzburg-Landau equation
birefringent fiber
Opis:
In this article, we consider the coupled Ginzburg–Landau equation with variable coefficients including the nonlinear gain and obtain the exact solutions of chirped dark vector quasi-solitons via the ansatz method. Next, the propagation of chirped dark vector quasi-solitons is discussed to verify whether they can be transmitted stably in the birefringent optical fiber system. The numerical simulation shows that this can be achieved. We deeply add the small perturbation to the transmission of dark vector quasi-solitons to make the results above more general. The results further prove the correctness of our solutions.
Źródło:
Optica Applicata; 2021, 51, 1; 51-58
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An integrated model of production scheduling and maintenance planning under imperfect preventive maintenance
Model zintegrowany harmonogramowania produkcji i planowania obsługi technicznej w ramach niepełnej konserwacji zapobiegawczej
Autorzy:
Chen, X.
Xiao, L.
Zhang, X.
Xiao, W.
Li, J.
Powiązania:
https://bibliotekanauki.pl/articles/301817.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
aperiodic imperfect preventive maintenance
production scheduling
maintenance planning
immune clonal selection algorithm
total profit
nieokresowa niepełna konserwacja zapobiegawcza
harmonogramowanie produkcji
planowanie konserwacji
algorytm odpornościowej selekcji klonalnej
całkowity zysk
Opis:
For a successful company, machines are always required to work continuously to make more profit in a certain period. However, machines can be unavailable due to the scheduled maintenance activities or unexpected failures. Hence, a model connected production scheduling with maintenance planning for a production line which is composed of multiple machines is developed. Suppose preventive maintenance is imperfect and cannot renew all the machines. Age reduction factor and hazard rate increase factor are introduced to illustrate the imperfect character. Aperiodic preventive maintenance policy is adopted. Replacement as perfect maintenance could restore the machine “as good as new”. When and whether to perform replacement is based on a cost-time rate function which is defined to judge whether or not the preventive maintenance is economical. The objective of the joint model is to maximize the total profit which is composed of production value, production cost, maintenance cost (including the preventive maintenance cost and replacement cost), and tardiness cost (which is related to the job sequence and maintenance activities). To optimize the objective, immune clonal selection algorithm is utilized. The proposed model is validated by a numerical example.
Aby firma mogła działać z powodzeniem i przynosić większe zyski w danym okresie czasu, zainstalowane w niej maszyny muszą pracować w sposób nieprzerwany. Niestety, z powodu planowych działań obsługowych lub nieoczekiwanych awarii, maszyny są czasami wyłączane z produkcji. Dlatego też w niniejszym artykule opracowano model łączący harmonogramowanie produkcji z planowaniem obsługi technicznej dla linii produkcyjnej złożonej z wielu maszyn. W pracy założono, że konserwacja zapobiegawcza jest niepełna i nie prowadzi do odnowy wszystkich maszyn. Aby zilustrować jej niepełny charakter, wprowadzono pojęcia czynnika redukcji wieku oraz czynnika wzrostu wskaźnika zagrożenia. Przyjęto politykę nieokresowej konserwacji zapobiegawczej. Wymiana jako forma pełnej konserwacji pozwala na przywrócenie maszyny do stanu "fabrycznej nowości". Kiedy i czy należy przeprowadzić wymianę zależy od funkcji wskaźnika kosztu w stosunku do czasu, który pozwala ocenić, czy konserwacja zapobiegawcza jest opłacalna. Model zintegrowany ma na celu maksymalizację całkowitego zysku, który jest wypadkową wartości produkcji, kosztów produkcji, kosztów obsługi (w tym kosztów konserwacji zapobiegawczej oraz kosztów wymiany) i kosztów nieterminowego zakończenia zadania (ang. lateness, związanych z kolejnością wykonywanych zadań i czynności obsługowych). Aby zoptymalizować opisany cel, wykorzystano algorytm odpornościowej selekcji klonalnej Proponowany model zweryfikowano na przykładzie liczbowym.
Źródło:
Eksploatacja i Niezawodność; 2015, 17, 1; 70-79
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental investigation of a high temperature resistant and low friction fracturing fluid
Autorzy:
Xiao, B.
Zhang, S.
Zhang, J.
Hou, T.
Guo, T.
Powiązania:
https://bibliotekanauki.pl/articles/109339.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
high temperature fracturing fluid
resistance to shearing
hydroxypropyl guar
low friction
delayed crosslinking
Opis:
The performance of a hydraulic fracturing fluid (HFF) system directly determines the efficiency of stimulation. Since the targeted formations of most oil fields in China are characterized by large depth (~5000 m), high temperature (160 to 180 °C) and tight lithology, newer and suitable HFFs have to be developed. Based on a newly synthetized organo-boron/-zirconium cross-linking agent (Gh-g), a composite temperature stabilizer (WJ-6) and other optimized additives via indoor evaluation, this study introduced a novel HFF, which is thermally stable at high temperature (HT) up to 180 °C and exerted low friction pressures. The performance of HFF was evaluated in the laboratory. The experimental results showed that the HFF system performed well at HTs. It maintained a viscosity of 100 mPa•s or more after 90 min of shearing (170 s−1) at 180 °C. Furthermore, the system exhibited delayed cross-linking. It took 120 s for the cross-linking reaction to complete; therefore, the tube friction was reduced to a large extent. Another characteristic feature of the formulated HFF system was the low friction pressures, where the drag reduction percentage was in the range from 35% to 70%. Moreover, only minor damage was caused by the fluid to the formation core samples. The average core permeability damage was 19.6%. All these qualities ensure that this fluid system is in full compliance with the requirements of the fracturing treatment.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 1; 37-47
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Specified weight cutting system for irregular solid material based on 3D scanning
Autorzy:
He, Jiadong
Huang, Yafeng
Zang, Xiao
Zhang, Yajun
Powiązania:
https://bibliotekanauki.pl/articles/2173699.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
specified weight
3D scanning
reverse engineering
calculation algorithm
waga określona
skanowanie 3D
inżynieria odwrotna
algorytm obliczeniowy
Opis:
A specified weight-cutting system for irregular solid materials such as rubber is important for industrial engineering. Currently, the workers’ experience is used, which has low accuracy and efficiency. A specified weight cutting system for irregular solid material based on 3D scanning is proposed in this paper, which aims to overcome the inaccuracy and inefficiency of the manual cutting process. Firstly, the surface of the irregular solid material is scanned by a tracking 3D laser scanner, and a triangular mesh file is generated. Secondly, the defects of the 3D model are repaired by reverse engineering, and then the 3D model file of the irregular objects is generated. Finally, the cutting position of the specified weight solid material is calculated by the calculation algorithm in UG software. In short, this research creates a new method for processing data collected by the 3D scanner, by working jointly with multiple devices and software, facilitating the cutting of irregular solid materials with specified weights. Additionally, the system has the advantage of accuracy and efficiency over the experience of workers.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 5; art. no. e143108
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Screening of high-efficiency potassium-dissolving strains and optimization of the potassium-dissolving process
Autorzy:
Xue, Yongping
Xiao, Chunqiao
Zhang, Yantu
Chi, Ruan
Powiązania:
https://bibliotekanauki.pl/articles/1447601.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
microorganism
potassium bacteria
potassium solubilization
potassium release
optimization of potassium-dissolving process
Opis:
The biosolubilization of potassium feldspar (K-feldspar) by potassium-dissolving microorganisms has become a hot research topic. However, the screening of highly efficient potassiumdissolving strains from the soils of mining areas has not been reported. In this study, 82 strains with potassium-dissolving ability were screened from soils collected from a K-feldspar mining area in Suizhou, Hubei Province, China. One of them, JX-20, was a gram-positive is spherical bacteria with smooth edges, which was identified as a new strain by 16S rRNA gene sequencing. Simultaneously, the influences of temperature, initial pH value, inoculation volume, incubation time, shaking speed, Kfeldspar concentration, K-feldspar granularity, and the ammonium sulfate dose on the potassium releasing ability of the JX-20 strain were investigated. The results showed that the JX-20 strain had an obvious dissolution effect on K-feldspar. The optimum conditions for the JX-20 strain to remove potassium from K-feldspar were as follows: cultured at 28-30℃ for ten days, initial pH value of 7.4-8, 60 mL medium in a 250 mL conical flask, and 170 r/min shaking speed on a rotary shaker. The Kfeldspar concentration, inoculation volume, K-feldspar granularity, and ammonium sulfate dose were 2 g/L, 20%, 0.02-0.03 mm, and 0.4 g/L, respectively. Under the above conditions, the highest corrosion efficiency of 39.75% was achieved.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 2; 1-13
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Structure and Magnetic Exchange Interaction in Fe₂NiAs Compound
Autorzy:
Wei, Xiao-Ping
Zhang, Ya-Ling
Sun, Xiao-Wei
Song, Ting
Zhu, Xing-Feng
Powiązania:
https://bibliotekanauki.pl/articles/1033418.pdf
Data publikacji:
2017-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Lp
71.20.Gj
71.20.-b
77.80.B-
Opis:
Using the spin-polarized relativistic Korringa-Kohn-Rostoker method, we study the electronic and magnetic properties of Fe₂NiAs compound with the Hg₂CuTi structure. Electronic calculations reveal the d-d orbital hybridization taking an important role in the compound. The calculated magnetic moments, which contain the spin and orbital moments, are primarily carried by Fe atoms located in A and B sites. The orbital moment of Fe₂NiAs system is rather small due to the cause of orbital quenching, implying a weak spin-orbit coupling. Simultaneously, we also study the influence of lattice constant on the magnetic moment, it is found that both spin and orbital moments are sensitive to the changes of lattice constants, i.e., the moments become larger as the expansion of lattice constant, indicating the enhancement of spin-orbit coupling effect. In addition, we investigate the magnetic interactions between the constituents to obtain the Heisenberg exchange coupling parameters. It is noted that the interactions are dominated by a strong exchange between Fe atoms. Finally, we acquire the Curie temperatures of Fe₂NiAs compound under different lattice constants by using mean field approximation.
Źródło:
Acta Physica Polonica A; 2017, 132, 4; 1320-1324
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrorefining of High Carbon Ferromanganese in Molten Salts to Produce Pure Ferromanganese
Autorzy:
Xiao, S.J.
Liu, W.
Gao, L.
Zhang, J.
Powiązania:
https://bibliotekanauki.pl/articles/353411.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high carbon ferromanganese
electrorefining
molten salts
pure ferromanganese
Opis:
High carbon ferromanganese is used as a starting material to prepare pure ferromanganese by electrorefining in molten salts. High carbon ferromanganese was applied as the anode, molybdenum was the cathode and Ag/AgCl was the reference electrode. The anodic dissolution was investigated by linear polarization in molten NaCl-KCl system. Then potentiostatic electrolysis was carried out to produce pure ferromanganese from high carbon ferromanganese. The cathodic product was determined to be a mixture of manganese and iron by x-ray diffraction (XRD). The content of carbon in the product was analyzed by carbon and sulfur analyzer. The post-electrolysis anode was characterized by scanning electron microscope (SEM). The mechanism of the anode dissolution and the distribution of the main impurity of carbon and silicon after electrolysis were discussed.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 3; 1505-1509
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Feasibility study of RANS in predicting propeller cavitation in behind-hull conditions
Autorzy:
Zhang, Yuxin
Wu, Xiao-ping
Lai, Ming-yan
Zhou, Guo-ping
Zhang, Jie
Powiązania:
https://bibliotekanauki.pl/articles/1573849.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
RANS
Computational Fluid Dynamics (CFD)
propeller cavitation
turbulence model
grid sensitivity
Opis:
The propeller cavitation not only affects the propulsive efficiency of a ship but also can cause vibration and noise. Accurate predictions of propeller cavitation are crucial at the design stage. This paper investigates the feasibility of the Reynolds-averaged Navier–Stokes (RANS) method in predicting propeller cavitation in behind-hull conditions, focusing on four aspects: (i) grid sensitivity; (ii) the time step effect; (iii) the turbulence model effect; and (iv) ability to rank two slightly different propellers. The Schnerr-Sauer model is adopted as the cavitation model. A model test is conducted to validate the numerical results. Good agreement on the cavitation pattern is obtained between the model test and computational fluid dynamics. Two propellers are computed, which have similar geometry but slightly different pitch ratios. The results show that RANS is capable of correctly differentiating the cavitation patterns between the two propellers in terms of the occurrence of face cavitation and the extent of sheet cavitation; moreover, time step size is found to slightly affect sheet cavitation and has a significant impact on the survival of the tip vortex cavitation. It is also observed that grid refinement is crucial for capturing tip vortex cavitation and the two-equation turbulence models used – realizable k-ε and shear stress transport (SST) k-ω – yield similar cavitation results.
Źródło:
Polish Maritime Research; 2020, 4; 26-35
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 50

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