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DINAME 2017
XVII International Symposium on Dynamic Problems of Mechanics
Identification of rotordynamic seal coefficients by means of impedance matrix and an optimization strategy
Submission Author:
Thiago Ritto , RJ
Co-Authors:
David Julian Gonzalez Maldonado, Thiago Ritto, Fernando Augusto de Noronha Castro Pinto
Presenter: David Julian Gonzalez Maldonado
doi://10.26678/ABCM.DINAME2017.DIN17-0205
Abstract
Theoretical modeling and experimental identification of annular seals parameters have been a challenge in the last 50 years due to the complex behavior of fluid inside these components. The complexity comes from the fluid dynamics that may create rotordynamic instabilities. A way to analyze instabilities in rotating machines with this kind of seals is by estimating the four main coefficients: direct stiffness and damping and cross-coupled stiffness and damping. For that reason, this paper presents and compares two methods to estimate seals coefficients using force and displacements measurements. The first method, the impedance matrix, uses position and force measurements at a fixed rotational speed of the machine to determine the seal matrix impedance. The real parts of the matrix are the stiffnesses and the imaginary parts the damping. On the other hand, the optimization method is based on a frequency sweep to compute the frequency response function (FRF), using position an force measurements. Then, an optimization algorithm is used to find the set of coefficients that best fits the experimental FRF. In the present stage of this research, only simulated data, with added Gaussian noise, is used to test the identification strategies.
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