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Wyszukujesz frazę "fluid film" wg kryterium: Temat


Wyświetlanie 1-7 z 7
Tytuł:
Analysis of contact mixing with boundary and hydrodynamic fluid films considering boundary slippage
Analiza kontaktu mieszanego z uwzględnieniem poślizgu brzegowego w strefie hydrodynamicznego filmu
Autorzy:
Zhang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/280086.pdf
Data publikacji:
2010
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
boundary film
nanometer-scale thin film
fluid film
boundary slippage
Opis:
An analysis is presented for a micro-contact where boundary and hydrodynamic fluid films simultaneously occur considering boundary slippage appearance at the upper contact surface in the boundary film area. The contact is one-dimensional, composed of two parallel plane surfaces, which are respectively rough rigid with rectangular projection in profile and ideally smooth rigid. In the outlet zone of the contact a boundary film occurs, and in the inlet zone of the contact a conventional hydrodynamic fluid film emerges. In the boundary film area, the film slips at the upper contact surface due to the limited shear stress capacity of the film-contact interface, while the film does not slip at the lower contact surface due to the shear stress capacity of the film-contact interface, which is large enough. In the boundary film area, the viscosity and density of the film are varied across the film thickness due to the film-contact interactions, and their effective values are used in modelling which depends on the boundary film thickness. In the fluid film area, the film does not slip at either of the contact surfaces.
Analiza zaprezentowana w pracy dotyczy zagadnienia mikro-kontaktu w strefie jednoczesnego występowania brzegowego i hydrodynamicznego filmu płynu z możliwością poślizgu w strefie brzegowej na górnej powierzchni kontaktu. Rozważany kontakt jest jednowymiarowy i odnosi się do dwóch równoległych płaskich powierzchni, z których jedna jest sztywna i szorstka w przekroju prostopadłym, a druga tak samo sztywna lecz idealnie gładka. W obszarze wyjścia ze strefy kontaktu pojawia się brzegowy film płynu, natomiast w strefie wejścia konwencjonalny film hydrodynamiczny. W strefie brzegowej film ulega poślizgowi na górnej powierzchni wskutek ograniczonej zdolności przenoszenia naprężeń stycznych pomiędzy płynem a ścianką, natomiast na powierzchni dolnej poślizg nie występuje. W strefie brzegowej filmu jego lepkość i gęstość zmienia się wzdłuż grubości wskutek interakcji płynu z powierzchnią. Efektywne wartości użyte w modelowaniu kontaktu zależą od grubości filmu brzegowego. W regularnej strefie film nie ulega poślizgowi na żadnej z omawianych powierzchni.
Źródło:
Journal of Theoretical and Applied Mechanics; 2010, 48, 1; 191-205
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
State-of-the-art rotordynamic analyses of pumps
Autorzy:
Gaulard, Frédéric
Schmied, Joachim
Fuchs, Andreas
Powiązania:
https://bibliotekanauki.pl/articles/2086884.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
rotordynamics
lateral analysis
pump
fluid-film bearing
pump seal
nonlinear analysis
dynamika wirnika
pompa
uszczelnienie pompy
analiza nieliniowa
Opis:
State-of-the-art analyses for the rotordynamic assessment of pumps and specific requirements for the simulation tools are described. Examples are a horizontal multistage pump with two fluid film bearings in atmospheric pressure, a horizontal submerged multistage pump with many bearings, and a submerged vertical single-stage pump with water-lubricated bearings. The rotor of the horizontal pump on two bearings is statically overdetermined by the seals and the static bearing forces depend on the deflection in the seals and the bearings. The nonlinear force-displacement relation in the bearings is considered in this paper. The stability of pumps is assessed by Campbell diagrams considering linear seal and bearing properties. Cylindrical bearings can have a destabilizing effect in the case of low loads as in the examples of the submerged pumps. For the pump with many bearings, the influence of the bearing ambient pressure and the bearing specific load on the stability is analyzed. For the vertical pump, the limit cycle, i.e. the vibration level of stabilization, is determined with a nonlinear analysis. All examples have a practical background from engineering work, although they do not exactly correspond to real cases. Analyses were performed with the rotordynamic software MADYN 2000.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 6; e139316, 1--12
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vibro-acoustic analysis of laminated double glazing using the force identification method
Autorzy:
Ben Jdidia, M
Akrout, A
Tounsi, D
Fakhfakh, T.
Haddar, M.
Powiązania:
https://bibliotekanauki.pl/articles/949211.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
fluid-structure interaction
thin-film laminated plate
ICA
excitation force
Kurtosis
Opis:
This paper presents a procedure for identifying wave forms and excitation frequencies of some forces applied on a given complex fluid-structure coupled system by using only its vibro-acoustic response. The considered concept is called the Independent Component Analysis (ICA) which is based on the Blind Source Separation (BSS). In this work, the ICA method is exploited in order to determine the excitation force applied to a thin-film laminated double glazing system enclosing a thin fluid cavity and limited by an elastic joint. The dynamic response of the studied fluid-structure coupled system is determined by finite element discretization and minimization of the homogenized energy functional of the coupled problem. This response will serve as the input for the ICA algorithm in order to extract the applied excitation.
Źródło:
Journal of Theoretical and Applied Mechanics; 2014, 52, 4; 895-904
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transient simulation of a squeeze film damped turbocharger rotor under consideration of fluid inertia and cavitation
Autorzy:
Drapatow, Thomas
Alber, Oliver
Woschke, Elmar
Powiązania:
https://bibliotekanauki.pl/articles/2090678.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
rotor dynamics
journal bearings
squeeze film damper
fluid inertia
dynamika wirnika
łożysko ślizgowe
bezwładność cieczy
Opis:
Squeeze film dampers (SFDs) are commonly used in turbomachinery in order to introduce external damping, thereby reducing rotor vibrations and acoustic emissions. Since SFDs are of similar geometry as hydrodynamic bearings, the REYNOLDS equation of lubrication can be utilised to predict their dynamic behaviour. However, under certain operating conditions, SFDs can experience significant fluid inertia effects, which are neglected in the usual REYNOLDS analysis. An algorithm for the prediction of these effects on the pressure build up inside a finite-length SFD is therefore presented. For this purpose, the REYNOLDS equation is extended with a first-order perturbation in the fluid velocities to account for the local and convective inertia terms of the NAVIER-STOKES equations. Cavitation is taken into account by means of a mass conserving two-phase model. The resulting equation is then discretized using the finite volume method and solved with an LU factorization. The developed algorithm is capable of calculating the pressure field, and thereby the damping force, inside an SFD for arbitrary operating points in a time-efficient manner. It is therefore suited for integration into transient simulations of turbo machinery without the need for bearing force coefficient maps, which are usually restricted to circular centralized orbits. The capabilities of the method are demonstrated on a transient run-up simulation of a turbocharger rotor with two semi-floating bearings. It can be shown that the consideration of fluid inertia effects introduces a significant shift of the pressure field inside the SFDs, and therefore the resulting damper force vector, at high oil temperatures and high rotational speeds. The effect of fluid inertia on the kinematic behaviour of the whole system on the other hand is rather limited for the examined rotor.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 6; e139201, s. 1--8
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Curvilinear squeeze film bearing lubricated with a DeHaven fluid or with similar fluids
Autorzy:
Walicka, A.
Jurczak, P.
Falicki, J.
Powiązania:
https://bibliotekanauki.pl/articles/264447.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
DeHaven fluid
modified Reynolds equation
squeeze film
mechanical parameters of the bearing
łożysko
równanie Reynoldsa
płyn nienewtonowski
Opis:
In the paper, the model of a DeHaven fluid and some other models of non-Newtonian fluids, in which the shear strain rates are known functions of the powers of shear stresses, are considered. It was demonstrated that these models for small values of material constants can be presented in a form similar to the form of a DeHaven fluid. This common form, called a unified model of the DeHaven fluid, was used to consider a curvilinear squeeze film bearing. The equations of motion of the unified model, given in a specific coordinate system are used to derive the Reynolds equation. The solution to the Reynolds equation is obtained by a method of successive approximations. As a result one obtains formulae expressing the pressure distribution and load-carrying capacity. The numerical examples of flows of the unified DeHaven fluid in gaps of two simple squeeze film bearings are presented.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 3; 697-715
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical parameters of the squeeze film curvilinear bearing lubricated with a Prandtl fluid
Autorzy:
Walicka, A.
Walicki, E.
Powiązania:
https://bibliotekanauki.pl/articles/265737.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
równanie Reynoldsa
płyn Prandtla
parametry mechaniczne
łożysko
additives
mechanical parameters of bearing
squeeze film
Prandtl fluid
modified Reynolds equation
Opis:
Based upon a Prandtl fluid flow model, a curvilinear squeeze film bearing is considered. The equations of motion are given in a specific coordinate system. After general considerations on the Prandtl fluid flow these equations are used to derive the Reynolds equation. The solution of this equation is obtained by a method of successive approximation. As a result one obtains formulae expressing the pressure distribution and load-carrying capacity. The numerical examples of the Prandtl fluid flow in gaps of two simple bearings are presented.
Źródło:
International Journal of Applied Mechanics and Engineering; 2016, 21, 4; 967-978
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Curvilinear squeeze film bearing with porous wall lubricated by a Rabinowitsch fluid
Autorzy:
Walicka, A.
Walicki, E.
Jurczak, P.
Falicki, J.
Powiązania:
https://bibliotekanauki.pl/articles/266104.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
non-Newtonian fluid
Rabinowitsch model
curvilinear squeeze film bearing
porous layer
płyn nieniutonowski
model Rabinowitscha
łożysko ślizgowe
warstwa porowata
Opis:
The present theoretical analysis is to investigate the effect of non-Newtonian lubricant modelled by a Rabinowitsch fluid on the performance of a curvilinear squeeze film bearing with one porous wall. The equations of motion of a Rabinowitsch fluid are used to derive the Reynolds equation. After general considerations on the flow in a bearing clearance and in a porous layer using the Morgan-Cameron approximation the modified Reynolds equation is obtained. The analytical solution of this equation for the case of a squeeze film bearing is presented. As a result one obtains the formulae expressing pressure distribution and load-carrying capacity. Thrust radial bearing and spherical bearing with a squeeze film are considered as numerical examples.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 2; 427-441
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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