Instability and heuristic problems in high - speed rotor of a micro turbine
Wybrane pełne teksty z tego czasopisma
Nonlinear forms of vibrations in rotors dynamics, especially after exceeding the stability limit, as well as the assessment of not precise and randomly variable input parameters, still constitute the research subject in many institutions all over the world. The results of investigations of the high-speed rotor of a micro turbine, being an element of the micro power plant in dispersed power engineering based on renewable energy sources - are presented in the paper. The basic problem of such devices is to assure a stable rotor operation within the entire range of rotational speeds. Foil bearings and special rotor structure were applied. It turned out that the situation in that the rotor - after loosing its stability - stabilises again when the rotational speed increases, is possible. This is a new phenomenon determined by the author as 'multiple whirls'. Possibilities of stabilizing the situation by the application of hybrid lubrication and siphon pockets are also presented in the paper. Another topic, discussed in the hereby paper, is an assessment of the influence of a random character of certain input data - in this case - changes of external excitations of the system. This problem is related to the so-called heuristic models often placed in opposition to widely used algorithmic models. The obtained results indicate different influence of disturbances depending on the system working conditions. After exceeding the stability limit, it means in a highly nonlinear operation range, the influence of disturbances significantly decreases. It is rather unexpected result. Research tools such as computer series codes and the method of their experimental verification are also included in the paper.
Bibliogr. 7 poz., rys., wykr., tab.
-  KICINSKI J., Rotor Dynamics, IFFM Publishers, ISBN 83-7204-542-9, pp. 539, Gdansk, 2006.
-  BATKO W., DABROWSKI Z., KICINSKI J., Nonlinear Effects In Technical Diagnostics, Publishing and Printing House of the Institute for Sustainable Technologies, ISBN 978-83-7204-748-9, pp. 303, Warszawa, 2008.
-  KICINSKI J., Materials and Operational Imperfections in Rotating Machinery, IFToMM – Seventh International Conference on Rotor Dynamics, Vienna (Austria), Paper-ID 307.
-  ZYWICA G., Simulation Investigation of the Effect of a Supporting Structure Defect on the Dynamic State of the Rotor Supported on Slide Bearings, ASME International Design Engineering Technical Conference, Las Vegas, DETC2007-34415.
-  KICIŃSKI J., ŻYWICA G., BANASZEK S., BOGULICZ M., CZOSKA B., Modelling of Thermo-Elastic Deformations of the Foil Bearing Bush with the Application of Authors’ Own and Commertial Calculation Codes (in polish), Internal Report No 22/08 of the IF-FM PAS,Gdansk 2008.
-  KU R., HESHMAT H.: Compliant Foil Bearing Structural Stiffness Analysis: Part II – Experimental Investigation. ASME Journal of Tribology, Vol. 115 (1993), 364-369.
-  PIETKIEWICZ P., KICIŃSKI J., CZOSKA B., MARKIEWICZ A., Development of Defect Models – with Uncertainty of Input Data Taken into Account (in polish), Internal Report of the IF-FMPAS, Gdansk 2008