Numerical evaluation of an identification technique for flexibly supported rigid turbomachinery foundations

Abstract

Appropriate modelling of turbomachinery foundations of existing installations is essential for determining the vibration behaviour of the machine. Earlier work had shown that provided one has an accurate rotor model and provided the system response is periodic, a practically feasible approach for identifying the relevant foundation parameters was possible in just two rundowns (one rundown only if the unbalance distribution is known) when the foundation consisted of simple pedestals. This paper generalises the approach to identifying all rigid body modes of a flexibly supported rigid foundation, allowing for the possibility of coupling or cross talk between the bearing supports. Numerical experiments show that the proposed approach is theoretically sound and practically realisable, in that identification is possible with 2 digit measurement accuracy, and potential problems of bearing force evaluations are circumvented.

Keywords:

• foundation identification
• rotordynamics
• non-linear rotor bearing foundation systems

Additional information

Notes on contributors

N Feng

Dr. Ningsheng Feng received his PhD degree from UNSW, Australia in 1988 and his BE degree from Zhejiang University, China in 1982.

Since 1991, he has been working in the School of Mechanical and Manufacturing Engineering, UNSW as a research associate, senior research associate, and lecturer. He was a lecturer at Yangzhou Institute of Technology (now part of Yangzhou University) from 1989 to 1991, a teaching and research assistant in Zhejiang University from 1982 to 1984, and a lathe operator in a machinery factory in China from 1969 to 1978.

His current research interests include: vibration analysis and diagnosis of rotor bearing foundation systems; identification of dynamic characteristics/faults of components in rotating machinery; mechanical machine design.

E J Hahn

Dr. Hahn began his career as mechanical engineering cadet at Duly and Hansford Ltd (now TRW Australia Pty Ltd), Sydney in 1959. He completed his doctorate on thrust bearings at UNSW in 1967 and after a couple of years as a research and development engineer, he joined the academic staff of the University of Virginia, USA as an assistant professor in 1969 and began his research interests in bearing dynamics and squeeze film dampers. He joined UNSW as a lecturer in 1972 where he expanded his research interest to rotor bearing foundation dynamics and where he retired as a professor of mechanical engineering in 1992 and is currently an Emeritus Professor.