Artykuły (WM)

Stały URI dla kolekcjihttp://hdl.handle.net/11652/206

Przeglądaj

Filtry

2007 - 200922010 - 20154

Ustawienia

Autorsearch.filters.applied.operator.equals: search.filters.author.Kozanecka, Dorota

collection.search.results.head

Teraz wyświetlane 1 - 6 z 6
  • Pozycja
    Investigations of Oil-Free Support Systems to Improve the Reliability of ORC Hermetic High-Speed Turbomachinery
    (Wydawnictwo Politechniki Łódzkiej ; Katedra Dynamiki Maszyn - Wydział Mechaniczny Politechniki Łódzkiej, 2011) Tkacz, Eliza; Kozanecka, Dorota; Kozanecki, Zbigniew; Miazga, Kacper
    The design of a small turbo-generator to produce electricity in the range from a few kWs requires the use of an aerostatic or aerodynamic gas bearing system. The theoretical analysis and the experimental test at the present stage of the study show that such highly rotating constructions are feasible. The problem consists in the optimal design selection from the viewpoint of the machine reliability and the adjustments are connected to the diminution in static thrust and lateral loads of the bearings by a correct design of the turbine flow structure and a correct selection of the gas bearing type.
  • Pozycja
    Niekonwencjonalne bezolejowe łożyska wysokoobrotowe turbogeneratora dla obiegu ORC.
    (Wydawnictwo Politechniki Łódzkiej. Instytut Maszyn Przepływowych, 2013) Kozanecki, Zbigniew; Kozanecka, Dorota; Łagodziński, Jakub; Tkacz, Eliza
    Obecnie w małych nowoczesnych systemach produkcji energii najczęściej stosowane są mikroturbiny o mocy rzędu od 1 do 20 kW. Niezwykle istotny jest rozwój niezawodnej technologii łożyskowania wirników tych miniaturowych maszyn przepływowych. Prezentowany w artykule układ wirujący turbogeneratora podparto w bezolejowych łożyskach foliowych. Podatne łożyska foliowe są rodzajem łożysk hydrodynamicznych, które wykorzystują gaz z otoczenia jako czynnik smarujący, co znacząco upraszcza ich konstrukcję.
  • 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.
  • Pozycja
    Experimental identification of dynamic parameters for active magnetic bearings.
    (Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej, 2008) Kozanecka, Dorota; Kozanecki, Zbigniew; Lech, Tomasz
    In the paper, an experimental identification procedure of dynamic parameters for active magnetic bearings is presented. In the proposed method, analysis of variable components of displacements of the rotor for an excitation with the rotating vector force of unbalance, is conducted. Proportionality of the bearing magnetic response force to the excitation force in the whole range of rotational frequency, is assumed. It allows for identification of equivalent dynamic coefficients of the bearing. The experimental investigations were carried out on test rigs with the shaft supported in active magnetic bearings.
  • Pozycja
    Application of active magnetic bearings for identification of the force generated in the labirynth seal.
    (Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej, 2007) Kozanecka, Dorota; Kozanecki, Zbigniew; Lech, Tomasz; Kaczmarek, Andrzej
    A magnetic bearing system of a rotating shaft is characterized by a unique feature that consists in the possibility of monitoring static and dynamic loads (reactions) of each bearing under normaI operation of the machine. In the paper, an identification procedure of bearing response forces, which allows for simultaneous measurement of the journal position with respect to the bush and the controI currents that flow in magnetie bearing bush windings, is presented. The proposed procedure ensures effective protection of the rotating shaft supported in active magnetic bearings against too high loads and displacements that can occur in the rotating system. Experimental investigations were carried out on test rigs wit h the shaft supported in active magnetic bearings.