Wydział Mechaniczny / Faculty of Mechanical Engineering / W1

Stały URI zbioruhttp://hdl.handle.net/11652/1

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20153

Ustawienia

Autorsearch.filters.applied.operator.equals: search.filters.author.Łagodziński, JakubTematsearch.filters.applied.operator.equals: search.filters.subject.dynamical systems - conference

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Teraz wyświetlane 1 - 3 z 3
  • Pozycja
    Influence of intermediate foil on air-foil bearings performance and exploitation properties.
    (Politechnika Łódzka. Wydział Mechaniczny. Katedra Automatyki, Biomechaniki i Mechatroniki., 2015) Łagodziński, Jakub; Miazga, Kacper
    Air-foil technology is an interesting alternative for classic rolling or oil bearings in turbomachinery. It ensures low power losses, do not require external lubrication or pressurization and is capable of working with high rotational speeds. Numerous studies brought significant improvement in materials and design solutions for the aerodynamic shaft support system. The paper presents effects of modification performed by adding intermediate foil to typical structure of air-foil bearing. The main aim of the investigation was focused on analyze of its influence on characteristic parameters and exploitation properties of operating bearing, i.e. bearing load capacity and bearing resistance to thermal runaway phenomenon [4]. The thermal runaway is also known as foil bearing thermal instability. The tests confirmed proper behavior of the modified device and brought new knowledge in air-foil technology field.
  • Pozycja
    Theoretical analysis of the foil bearings dynamic characteristics.
    (Politechnika Łódzka. Wydział Mechaniczny. Katedra Automatyki, Biomechaniki i Mechatroniki., 2015) Tkacz, Eliza; Kozanecki, Zbigniew; Kozanecka, Dorota; Łagodziński, Jakub
    In the theoretical analysis, three systems were identified: a rotor, a gas film and a exible structure. The mathematical analysis involves formulation of analytical equations for each of these elements and determination of their interactions. It was found that the rotor dynamics was subject to Newton's second law of motion, the gas flow in the bearing could be described by the Reynolds equation, whereas a spring-damper model was selected for the structural analysis. The Reynolds equation is a differential equation the exact solution to which is unknown. The work describes the finite difference method in detail, where the partial derivatives in the Reynolds equation are replaced by a system of algebraic equations. In order to solve the resulting system, the Alternating Direction Implicit method (ADI) was used. Thanks to those calculations, it was possible to determine the bearing dynamic characteristics using both the linear and non-linear method.
  • Pozycja
    Model of the gas journal bearing dynamics with a exibly supported foil.
    (Politechnika Łódzka. Wydział Mechaniczny. Katedra Automatyki, Biomechaniki i Mechatroniki., 2015) Tkacz, Eliza; Kozanecki, Zbigniew; Kozanecka, Dorota; Łagodziński, Jakub
    The work is devoted to an analysis of the journal bearing dynamics employing a numerical model which takes into account factors related to motion and friction of non{rotating elements of the sleeve. This model yields the basis for simulations carried out in order to determine correctly dynamic characteristics of an oil{free machine rotating system at the early stage of its design and during its operation. On the basis of those simulations, the thickness of gas lm was determined as well as the pressure distribution in the bearing and its lift capacity. Moreover, the numerical program led to an analysis of proper vibrations and forced vibrations of the system under consideration. It was possible to obtain attenuation of the force and to visualize a journal trajectory for the dynamic harmonic input function. The FFT (Fast Fourier Transform) analysis of vibrations was implemented. In the spectrum, only a frequency of the input function was observed, whereas and a lack of subsynchronous frequencies pointed to the stable operation of the bearing.