LaBreVer

For future aircraft design, focus is placed on lower pollutant emissions and stable operations over an ever-bigger load of the engine. These developments often go hand in hand with investigations of the thermoacoustic response behaviour, since the appearance of thermoacoustic instabilities can impact the engine operation and lead to noise and, in the worst case, to damage of the system.

In the framework of the UTC TU Darmstadt, the institute STFS develops numerical models to add to the predictive assessment of the thermoacoustic response of gas turbine engine injectors.

LaBreVer uses experimental reference data measured by Rolls-Royce Deutschland at the SCARLET (Scaled Acoustic Rig for Low-Emission Technology) at DLR Cologne to validate both conventional and novel numerical methods.

Methodology

Conventional CFD: Using the Rolls-Royce in-house CFD solver PRECISE-UNS, compressible Large-Eddy Simulations (LES) spanning the entire range of physical processes in the combustion chamber are the primary reference method for novel development. Combustion models using a flamelet approach are available in the CFD solver, and are always further developed at Rolls-Royce and STFS.

Hybrid CFD-CAA: Runtime-coupling of low-Mach CFD simulations using PRECISE-UNS for fluid flow, and the Nektar++ CAA solver for acoustics, enables the case-by-case adaptations of different domains to the investigated scenarios. Coupling is realized using an external coupling library.

Key Scientific Takeaways

• General acoustic behaviour of even the complex SCARLET geometry could be well obtained using numerical counterparts.
• Simplifications impede the results, both using conventional and hybrid methods.
• Further focus must be on improved modelling of acoustically relevant geometrical features, which must be implemented in the numerical tools.
• Hybrid CFD-CAA still relies on additional modelling simplifications, which need to be investigated and assessed appropriately.

Related Projects

OptTuGen (opens in new tab) (2023 – 2026)

Funding and cooperation

Last- und Brennstoffflexible Verbrennung (Load and Fuel Flexible Combustion – LaBreVer) was a joint research program in the frame of AG Turbo. It was financially supported by the Federal Ministry for Economic Affairs and Climate Action (BMWK) under grant number 0324295D, and Rolls-Royce Deutschland. Calculations for this research were partly conducted on the Lichtenberg high performance computer of the TU Darmstadt.