The aviation industry undergoes a period of various changes. Aircraft turbines have to fulfill the legally binding emission limits, which are decreasing permanently. Further, a higher efficiency of the turbines is required, which can be obtained with higher pressure conditions in the turbines.
It was the objective of the GerMaTec project to reduce the emission of nitrogen oxides for saving the environment; with particular reference to the thermo-acoustic vibrations, which often occur in fuel atomizers running at a lean combustion mode.
The potential reductions of nitrogen oxide emissions with the conventional, existing technologies and methods are limited and cannot fulfill future requirements.
It is the aim to improve the new technology and minimize the occurring vibrations. The GerMaTec project focused on the development of methods to lower the vibrations inside the combustor. Special considerations were made for the operating characteristics (start and stability) and for the cooling technology.
The following concrete targets were formulated:
- Maximum emission level of nitrogen oxides at 45% of the CAEP6 limit. (CAEP= Committee on Aviation Environmental Protection)
- Measures to limit the amplitude of the vibrations to 0,2 bar.
The project was divided into several subprojects:
- Development of methods
- Diagnostic of the components
- Validation of several modules
In cooperation with the DLR Köln (national aeronautics and space research centre of the Federal Republic of Germany, Cologne), an accessible high pressure sector was developed: It is possible to observe the combustion behavior with laser technology.
To extend the capacities and scopes for tests at the DLR Köln, a further bench was installed. With the new bench, a maximum of 40 bar and 1000K can be reached during tests.
The research of the GerMaTec project contributes to the development of the lean combustion technology and can be seen as a further step to marketability. The project improved methods and design tools, which will lead to better constructions of the engine combustors in future.
Findings of the study are published by a final report (German only), which is available online via the Technical Information Library (TIB) of the Hannover University: http://edok01.tib.uni-hannover.de/edoks/e01fb12/685604586.pdf