0
Research Papers: Gas Turbines: Structures and Dynamics

Design of Electromagnetic Dampers for Aero-Engine Applications

[+] Author and Article Information
Andrea Tonoli

Department of Mechanics, Mechatronics Laboratory, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino, Italyandrea.tonoli@polito.it

Nicola Amati

Department of Mechanics, Mechatronics Laboratory, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino, Italynicola.amati@polito.it

Angelo Bonfitto

Mechatronics Laboratory, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino, Italyangelo.bonfitto@polito.it

Mario Silvagni

Mechatronics Laboratory, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino, Italymario.silvagni@polito.it

Bernard Staples

Whole Engine Modeling Department, Rolls-Royce Plc., P.O. Box 31, Derby DE24 8BJ, Englandbernard.staples@rolls-royce.com

Evgueni Karpenko

Whole Engine Modeling Department, Rolls-Royce Plc., P.O. Box 31, Derby DE24 8BJ, Englandevgueni.karpenko@rolls-royce.com

J. Eng. Gas Turbines Power 132(11), 112501 (Aug 05, 2010) (11 pages) doi:10.1115/1.4000801 History: Received March 05, 2009; Revised November 23, 2009; Published August 05, 2010; Online August 05, 2010

The vibration control of rotors for gas or steam turbines is usually performed using passive dampers when hydrodynamic bearings are not used. In layouts where the rotating parts are supported by rolling bearings, the damping is usually provided by squeeze film dampers. Their passive nature and the variability of their performances with temperature and frequency represent the main disadvantages. Dampers with magnetorheological and electrorheological fluid allow solving only a part of the abovementioned drawbacks. Active magnetic bearings (AMBs) are promising since they are very effective in controlling the vibration of the rotor and offering the possibility of monitoring the rotor’s behavior using their displacement sensors. However they show serious drawbacks related to their stiffness. Electromagnetic dampers seem to be a valid alternative to visco-elastic, hydraulic dampers due to, among the others, the absence of all fatigue and tribology issues resulting from the absence of contact, the small sensitivity to the working environment, the wide possibility of tuning even during operation, the predictability of the behavior, the smaller mass compared with AMBs, and the failsafe capability. The aim of the present paper is to describe a design methodology adopted to develop electromagnetic dampers to be installed in aero-engines. The procedure has been validated using a reduced scale laboratory test rig. The same approach has then been adopted to design the electromagnetic dampers for real civil aircraft engines. The results in terms of achievable vibration reductions, mass, and overall dimensions are hence presented. A trade-off between the various proposed solutions has been carried out evaluating quantitative performance parameters together with qualitative aspects that this “more electric” technology implies.

Copyright © 2010 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Sketch of an active magnetic damper in conjunction with a mechanical spring. They both act on the nonrotating part of the bearing.

Grahic Jump Location
Figure 2

Sketch of a two electromagnet semi-active magnetic damper (the elastic support is omitted)

Grahic Jump Location
Figure 3

(a) Mechanical impedance of a transformer eddy current damper in parallel to a spring of stiffness Km. (b) Mechanical equivalent and (c) SAMD Force to velocity transfer function (solid line: magnitude; dashed line: phase).

Grahic Jump Location
Figure 4

Rotordynamics test rig: (a) picture and (b) section view of the rotor of the machine and of the elastic supports. (1) LPT disk, (2) LPT roller bearing, (3) LPT beam support, (4) LPC beam support, (5) LPC ball bearing, (6) LPC disk, and (7) hollow shaft; (c) section view indicating the main nodes of the FE modeling.

Grahic Jump Location
Figure 5

Campbell diagram of the RTR (supported rotor) in solid line (left scale) and corresponding strain energies in dashed lines (right scale)

Grahic Jump Location
Figure 6

(a) Results of the sensitivity analysis: damper forces on LPC support varying the damping viscous coefficients of both the supports. (b) Results of the sensitivity analysis: Displacement of the LPC disk varying the damping viscous coefficients of both the supports.

Grahic Jump Location
Figure 7

(a) Unbalance response (displacements and velocities) of the RTR with the selected amount of equivalent viscous damping. (Dashed line: LPC disk; solid line: LPT disk) (b) Unbalance response (spring and damper forces) of the RTR with the selected amount of equivalent viscous damping. (Dashed line: LPC disk; solid line: LPT disk).

Grahic Jump Location
Figure 8

Sketch of the electromagnetic damper dimensions (refer to Table 1 for detailed dimensions)

Grahic Jump Location
Figure 9

Scheme of the complete control loop used in the AMD configuration

Grahic Jump Location
Figure 10

(a) Experimental RTR time history: (1) undamped system, (2) AMD system, and (3) SAMD system, AMD, and SAMD applied on LPC support. (b) Experimental versus model RTR transfer function (force on LPC disk on acceleration of the rotor at damper location): Effect of AMD and SAMD applied on LPC support compared with the undamped system. (solid line: experimental results; dashed line: mathematical model results; ◻: undamped system; ○: SAMD system; and △: AMD system). (c) Experimental versus model RTR unbalance response: Effect of AMD and SAMD applied on LPC. Support compared with the undamped system. (Solid line: experimental results; dashed line: mathematical model results; ◻: undamped system; ○: SAMD system; and △: AMD system).

Grahic Jump Location
Figure 11

Gas turbine engine.

Grahic Jump Location
Figure 12

Parametric analysis of the variation in (a) support stiffness and (b) support damping coefficient

Grahic Jump Location
Figure 13

Campbell diagram (not to scale) of the rotor ONLY connected to ground by means of support and stator equivalent stiffness (no stator dynamics are included). Supports (considered as equivalent stiffness) strain energies are reported.

Grahic Jump Location
Figure 14

(a) Unbalance response (not to scale): displacements of rotor node, (b) unbalance response (not to scale): velocities of reference node on stator, and (c) unbalance response (not to scale): forces exerted by the dampers

Grahic Jump Location
Figure 15

Sketch (not to scale) of the designed AMD inserted in the real engine

Grahic Jump Location
Figure 16

Detailed view (not to scale) of the designed AMD (a) for low pressure compressor support and (b) for low pressure turbine support

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In