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Wyszukujesz frazę "Sławiński, D." wg kryterium: Autor


Wyświetlanie 1-7 z 7
Tytuł:
Dynamic analysis of the control stage of a high speed steam turbine
Autorzy:
Sławiński, D.
Zakrzewski, W.
Powiązania:
https://bibliotekanauki.pl/articles/175498.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
control stage
residual stresses
initial displacement blade
vibrations blade
Opis:
This paper analyzes the possibility of resonances within a control stage of a high speed turbine. An original method for steady state operation is used for the analysis of the stiffness matrix representing: initial displacement blade (nominal shape blade obtained by nominal working point of turbine) and residual stresses following local crossing yield plastic strain. In the analysis there has been found a possibility of occurance of the resonance frequency, and mistuning by showing the safe working ranges. The calculation used the 3D modal and harmonic analysis within computational solid dynamics (CSD) and the results were compared with the 0D data from literature. After local crossing of yields stresses, on the basis of the harmonic analysis, there has been shown operation of the blade in the resonance point. Before crossing the yield stresses the blade is working in mistuning and a safe point.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2012, 124; 41-49
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A robust model of material degradation within a corrosive environment
Autorzy:
Majkowska, A.
Sławiński, D.
Badur, J.
Powiązania:
https://bibliotekanauki.pl/articles/175281.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
corrosion
material degradation
CSD simulation
Opis:
This paper is a proposition of implementation an amendment to the existing classic definition of degradation described the by Kachanov-Robotnov model. The proposed model allows to determine the rate of degradation the material structure in an independent verified corrosive environment and determining the redistribution of three-dimensional stress fields taking into account the progressive degradation. According to that purpose, the computational solid dynamics (CSD) numerical simulation of corrosion degradation performed with the mathematical model which was calibrated on the basis of an experiment has been performed by Mrowiec and Werber.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2015, 128; 85-96
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of unsteady flow forces on the thermowell of steam temperature sensor
Autorzy:
Kornet, S.
Sławiński, D.
Ziółkowski, P.
Badur, J.
Powiązania:
https://bibliotekanauki.pl/articles/175578.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
unsteady flow
resonance
CFD modeling
CSD modeling
Opis:
In this paper, 3D numerical analysis of unsteady flow forces acting on the thermowell of steam temperature sensor is presented. According to that purpose, the CFD+CSD (computational fluid–solid dynamics) approach has been used. The nonstationary of fluid acting on the thermowell such as: Strouhal frequency, amplitude of pressure, structure of vortex, peak of pressure, field of pressure, field of velocity, etc. are studied analytically and numerically. There have been examined two cases of flow with changing both temperature, pressure and mass flow rate (operating daily and night in the unit with capacity of 380 MWe). In accordance with the standards ASME PTC 19.3 TW-2010 the possibility of entry into resonance has been examined.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2015, 129; 25-49
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A role of the heat and work uncompensated transformations in the balance of entropy and the turbomachinery efficienc
Autorzy:
Kowalczyk, T.
Ziółkowski, P.
Sławiński, D.
Cisak, M.
Badur, J.
Powiązania:
https://bibliotekanauki.pl/articles/175450.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
entropy balance
entropy sources
uncompensated transformations
isentropic efficiency
polytropic efficiency
eulerian fluid
turbine stage
Puzyrewski number
Opis:
The notion of heat uncompensated transformation has early been introduced by Clausius in 1854 and next, after fifty years of forgetting, in 1904 Duhem has revalorized it and combined it with a new notion of work uncompensated transformation [3]. In this way the so-called ClausiusDuhem inequality has been established. In our paper we wish to present a novelized procedure of estimating the role of the uncompensated transformations of heat and work within the flow of viscous and heat conducting working fluid like water stream. The original procedure was introduced by Puzyrewski and it is essential in expressing of a local, in time and space, balance of entropy. Futhermore, this unique approach leads to redefinition of the efficiency notion, as is usually applied to fluid-flow machineries, to a new one important in computational fluid dynamics (CFD) three-dimensional modeling. As a result, it is shown that usage of the polytropic efficiency, instead of the isentropic efficiency, is more convenient and seems to be natural in CFD approach. Helpfully, we have also found a correlation between those two efficiency definitions with usage of proposed new dimensionless (criterion) number.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2017, 135; 11-27
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of the Baumann turbine stage operation Part II. Free and kinetic vibrations
Modelowanie pracy turbinowego stopnia Baumanna, część II – drgania swobodne i wymuszone kinetycznie
Autorzy:
Jesionek, K.
Kron, J.
Zakrzewski, W.
Sławiński, D.
Kornet, S.
Ziółkowski, P.
Badur, J.
Powiązania:
https://bibliotekanauki.pl/articles/172994.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
turbina kondensacyjna
stopień Baumanna
CSD
drgania swobodne
drgania wymuszone
condensing turbine
Baumann's stage
random vibrations
forced vibration
Opis:
In this paper has been presented a methodology of validation a novel mathematical model dedicated to evaluation and prediction of material degradation and damage of steam turbine elements such as blades, valves, and pipes due to three mechanisms: stress-corrosion, high-temperature creep and low-cyclic fatigue. The validation concept is based on an experimental setup manufactured in the Laboratory of Faculty of Mechanical and Power Engineering, Wrocław UT. The concept of validation by comparison of measured and numerically predicted eigen-frequencies and eigen-modes of different turbine elements within laboratory conditions are presented, and mathematical models of three damage mechanisms have been described. Using the mentioned method of experimental validation based on comparisons of eigen-frequencies, we could calibrate yet unknown coefficients in the turbine damage model. A practical aim is an implementation of a novel life-time module for the BOTT (block of thermal stresses restriction) system. In particular the stress-corrosion factor will be added for the advanced numerical control system, creating in such way a universal, flexible and a complete tool for monitoring degrees of degradation, corrosion and damage of critical points in a steam turbine.
Niniejszy artykuł jest kolejnym z cyklu, którego celem jest opracowanie numerycznego narzędzia badawczego opartego na CSD (Computational Solid Dynamics). Zadaniem jego byłaby weryfikacja stanu wytrzymałościowego i dynamicznego trudnodostępnych dla pomiarów urządzeń w turbinie takich jak: rurociągi pary świeżej, zawory, wirniki czy łopatki. Narzędzie obserwowałoby rozwijające się mechanizmy: korozji, pełzania wysokotemperaturowego i niskocyklicznego zmęczenia. Ostateczną walidacje modeli numerycznych z eksperymentem zaplanowano wykonać w Laboratorium Wydziału Mechaniczno-Energetycznego Politechniki Wrocławskiej. W tej części cyklu artykułów pokazano m.in. walidację modelu numerycznego z pomiarami drgań, jakie wykonano na stanowisku badawczym oraz w skrócie opisano poszczególne moduły narzędzia. Po implementacji wszystkich modeli do systemu nadzorującego pracę turbozespołu o nazwie BOTT (Blok Ograniczeń Termicznych), powstanie zupełnie nowy, elastyczny i kompletny system monitorujący stopień degradowania się elementów turbozespołu o nazwie ANCS (Advance Numerical Control Systems) działający w sposób on-line.
Źródło:
Archiwum Energetyki; 2013, 43, 1/2; 61--74
0066-684X
Pojawia się w:
Archiwum Energetyki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the internal efficienty of a turbine stage: classical and computational fuid dynamics definitions
Autorzy:
Nastałek, L.
Karcz, M.
Sławiński, D.
Zakrzewski, W.
Ziółkowski, P.
Szyrejko, C.
Topolski, J.
Werner, B.
Badur, J.
Powiązania:
https://bibliotekanauki.pl/articles/175251.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
turbine stage
stage power
stage efficiency
losses
Opis:
Almost entire fleet of steam turbines in Poland was designed between 1950_1980 with the use of the so-called zero-dimensional (0D) calculation tools. For several years, design and modernization of the turbines occur in assistance with the state-of-the-art methods that describe working fluid flow field based on three-dimensional (3D) models and computational fluid dynamics (CFD) codes. This cooperation between 0D and 3D codes requires exchange of overall, integral information such as: power, efficiency, heat and mass fluxes. In consequence the question arises regarding the cohesion of definitions, and particularly regarding the correctness of the definition for internal efficiency of the turbine's stage and the turbine as a whole. In the present paper we formulate basic definitions reason of efficiency that are naturally adapted to the numerical 0D and 3D models. We show that the main reason of differences between the definitions in 0D and 3D is the definition of the theoretical work of the stage lt. In the classical 0D models, mostly employed is the isentropic approach, and hence the isentropic efficiency occurs. Meanwhile, in the increasingly common 3D approach (most likely by CFD), we use more physically correct pathway by subtracting energy loss from the available energy, that leads to the polytropic definition of efficiency. We show an example of computing the efficiency and the 3D losses, denoted with additional subscript CFD, we also discuss benefits of this definition in comparison with the isentropic classical definition in 0D.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2012, 124; 17-39
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on carbon dioxide thermodynamic behavior for the purpose of shale rock fracturing
Autorzy:
Niezgoda, T.
Miedzińska, D.
Małek, E.
Kędzierski, P.
Sławiński, G.
Powiązania:
https://bibliotekanauki.pl/articles/201878.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
carbon dioxide
shale gas
storage system
thermodynamics
FEM
Opis:
The possibility of using CO2 to fracturing a shale rock has been presented in the paper. The described innovative method which allows for the efficient extraction of shale gas and carbon dioxide storage in a shale rock was developed in Department of Mechanics and Applied Computer Science at the Military University of Technology, Warsaw, Poland. Firstly, the method was verified on the base of analytical and experimental research. In the next stage of the method verification carbon dioxide thermodynamic behavior was studied. The growth in pressure of drop of CO2 heated in a closed volume was numerically tested. The research confirmed the efficiency of the use of carbon dioxide as a medium for fracturing of rocks. The usage of liquid CO2 can be alternative for hydraulic fracturing and is safe for the environment.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2013, 61, 3; 605-612
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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