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## Aeroelastic Numerical Investigation of Pressure Disturbances Induced by Pressure Gain Combustion in Gas Turbine Axial Compressors

- Static entropy contour and surface streamlines around a HPC rotor blade, for unsteady baseline and a selected disturbed case. (Rescaled Geometry)
- © TUB F1

This project assesses the unsteady operation of gas turbines, more specifically high pressure compressors, subject to disturbances stemming from pressure gain combustion (PGC) processes. Novel fuel-burning technologies in gas turbines (such as pulse or rotating detonation, wave rotor and resonant combustion) introduce periodic disturbances in the already unsteady flow field of the adjacent components, i.e., the compressor upstream and the turbine downstream. Fluctuations in flow variables induced by PGC imply interesting unsteady fluid dynamics phenomena but also unusual structural (aeroelastic) effects.

The unsteady operation of single and multirow setups is assessed to determine how performance parameters (such as isentropic efficiency, losses and pressure ratio) are affected by combustion disturbances. Identification techniques such as proper orthogonal decomposition and dynamic mode decomposition are applied to the unsteady results to better assess the origin and propagation of losses and high entropy regions within the domains. Additionally, the unsteady damping is computed, to evaluate how farther upstream the disturbances effectively propagate. The results pinpoint the potentially harmful disturbance ranges from the turbomachinery viewpoint, indicating how much of the promised thermodynamic efficiency improvements of pressure gain combustion might be hindered by component operation losses.

For the aeroelastic analysis, the forcing spectrum of the aerodynamics loads on the blades is calculated, comparing undisturbed and disturbed operation. Aerodynamic damping is computed by using time and frequency-domain methods such as the nonlinear harmonic balance. Mode-superposition forced response analyses may then indicate the actual effects of PGC in the dynamic stresses and displacements experienced by rotor blades in high pressure compressors.

Person of contact: Dipl.-Ing. (FH) Victor Bicalho

## References

*Unsteady Aerodynamics of a High Pressure Compressor Working under Pressure Gain Combustion Disturbances*

V. Bicalho Civinelli de Almeida, V. Motta, D. Peitsch

International Gas Turbine Congress 2019,

Tokyo, Japan, November 17-22 2019, IGTC2019-0070*Aeroelastic Assessment of a Highly Loaded High Pressure Compressor Exposed to Pressure Gain Combustion Disturbances*

V. Bicalho Civinelli de Almeida, D. Peitsch

Journal of the Global Power and Propulsion Society

Volume 2, October 2018, Pages 477-492

DOI: 10.22261/JGPPS.F72OUU*Multirow Performance and Aeroelastic Analyses of a Compressor Subjected to Disturbances from Pressure Gain Combustion*

V. Bicalho Civinelli de Almeida, D. Peitsch

ISUAAAT 15

Oxford, UK, September 24-27 2018, ISUAAAT15-031*Aeroelastic Assessment of a Highly Loaded High Pressure Compressor Exposed to Pressure Gain Combustion Disturbances*

V. Bicalho Civinelli de Almeida, D. Peitsch

Global Power and Propulsion Society Forum Montreal 2018,

Montreal, Canada, May 7-9 2017, GPPS-2018-29

DOI: 10.5281/zenodo.1342727