AMBIT: Active magnetic bearings in aircraft turbo-machinery

• Research unit: EU RFP
• Project number: 97.0289-2

Key words (English)

Active magnetic bearings; aircraft engines; high temperatures; load sharing

Alternative project number (English)

EU project number: BRPR-CT98-0623

Research programs (English)

EU-programme: 4. Frame Research Programme - 2.1 Industrial and materials technologies

Short description (English)

See abstract

Partners and International Organizations (English)

Imperial College London (UK); ETH Zürich (CH); TU Darmstadt (D); MTU München (D); EAA Wien (A); Turbomeca Bordes(F)

Abstract (English)

The main objective of AMBIT is the investigation of proposals for AMBs to be used in aeroengines in three areas: - Elevated-temperature operation of the AMBs with target of 540°C
- Dynamics of the rotor and bearings in extreme load conditions (load sharing)
- Alternative design concept studies to realise the full potential of using advanced AMBs
in aeroengines.
The project focused on investigating materials and designs to cope with these problems, and to develop reliable analytical tools to predict the dynamic performance. Four test rigs were developed.
The development of a high temperature AMB design was successful. A prototype demonstration rig was built at ETH which has achieved the required operating temperature of 540°C.
Experimental results from ETH on a contact test rig were difficult to reproduce with a realistic model, as it was not possible to determine the contact forces. Tests were performed on the ICL rig using step sine excitation generated through the AMBs and also force input through the base. The results highlight the need for better contact model data. The TUD touch-down test rig was completed late in the program. However it does provide a powerful research test rig for future investigations.
TUD has developed a new rotor modelling software which incorporates the contact model and a full electrical/control model for the AMBs. ICL produced a designer-orientated rotor modelling package, which can be used to make rapid design investigations for rotor dynamic.
The design evaluations were focused onto a single rotor system based on a helicopter engine. These showed that the AMBs could replace conventional bearings on the rotor, but the extra size of the AMBs asks for touch-down bearings which can carry part of the transient loads (load sharing). Hence such designs should incorporate a more radical approach, utilising the potential higher operating temperature and active control, to achieve maximum benefits.
Overall, the project has been a success, and the partners wish to continue investigations of AMBs in such applications.

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 97.0289-2