Limousine: Limit cycles of thermo-acoustic oscillations in gas turbine combustors
Limousine is a Marie Curie Initial Training network funded by the European Commission under Framework 7 for the period 2008-2012. It represents a multidisciplinary initiative to strengthen the fundamental scientific work in the field of thermo-acoustic instabilities in combustion systems, and is motivated by the need for lean combustion technologies and reduced emissions. The network comprises 12 partner institutions across Europe: 5 academic partners, 2 research institutions and 5 industrial partners. There is also an academic partner in the USA.
The research in Limousine will focus on the limit cycle behaviour of the unstable pressure oscillations in gas turbines, and on the resulting mechanical vibrations and materials fatigue. It will provide research training to young European scientists and engineers in mathematics, computational modelling, structural mechanics, acoustics, fluid mechanics, combustion experimental techniques, material science and control systems theory. It will help to generate a new generation of young engineering scientists, who are highly skilled in the development and application of design and operational tools, to keep thermo-acoustic induced vibration and fatigue within limits at all circumstances. A total of 20 research positions are offered.
Gas turbine engines are the most efficient engines for power generation at a large scale, combining a very compact design with low maintenance and high reliability. Their robustness, however, is dependent on their design and operating conditions. In the gas turbine, power is generated by burning fuel at high pressure and temperature. Feedback between the fuel combustion process and pressure waves can lead to violent oscillations in the engine. These are termed “thermo-acoustic instabilities”.
To predict the occurrence of severe thermo-acoustic instabilities in gas turbines over the entire load range, and assess their possible impact, it is essential to understand the processes that lead up to it. The main processes are: acoustic and aerodynamic effects on the combustion process, dynamic behaviour of the combustor structure, fatigue and fracture. This interaction of the various processes clearly indicates that expert knowledge is required from a number of scientific areas, and that a multi-disciplinary approach is the only way to address this difficult problem.
The project is coordinated by the University of Twente, group of Thermal Engineering, Dr. Jim Kok.