Experimental Investigation of Limit-Cycle Oscillations in an Unstable Gas Turbine Combustor

2002 ◽  
Vol 18 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Tim C. Lieuwen
Keyword(s):  
Experimental Investigation ◽  
Gas Turbine ◽  
Limit Cycle ◽  
Limit Cycle Oscillations ◽  
Gas Turbine Combustor

Analysis of Time-Signal of an Industrial Gas Turbine Combustor Under an Unstable Condition

2016 ◽  
Author(s):  
D. Lengani ◽  
P. Zunino ◽  
F. Romoli ◽  
E. Bertolotto ◽  
S. Rizzo
Keyword(s):  
Fourier Transform ◽  
Wavelet Transform ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Limit Cycle ◽  
Limit Cycle Oscillations ◽  
Unstable Condition ◽  
Gas Turbine Combustor ◽  
Time Space ◽  
Industrial Gas Turbine

This paper analyzes the time-signals of pressure sensors mounted in an industrial gas turbine combustor under an unstable condition. The present investigation is aimed at the discussion of the sudden increase in amplitude due to the limit-cycle oscillations and of its temporal evolution. To this purpose, different post-processing tools are described and adopted: i.e. wavelet transform, cross-correlations, time-space Fourier transform and proper orthogonal decomposition (POD). The properties of the wavelet transform are used in order to identify the time of occurrence and the frequency of the limit-cycle oscillations. They occur at the second harmonic of the natural frequency of the annular combustion chamber. The amplitude of the pressure fluctuations at this characteristic frequency increases to a critical value with very large amplitude in about 0.15s that corresponds to about 26 periods of the phenomenon. Within this period, the pressure signals from two neighboring burners have a quite large and increasing degree of correlation as it is observed from the cross-correlation of the signals. The time-space Fourier transform suggests that the instability couples with a natural mode of the combustion chamber. The azimuthal wave length of such mode is half of the combustion chamber circumference (this corresponds to an azimuthal mode 2). According to this findings, the POD is used to provide an identifier for the occurrence of the limit-cycle oscillations. In fact, POD is known to isolate the deterministic fluctuations based on an energy rank. Hence, the first POD mode isolates the effect of specific frequency forcing and its energy content is retained in the first POD eigenvalue which is used as identifier.

scholarly journals An experimental investigation on the maximum loading of a practical gas turbine combustor.

1986 ◽  
Vol 52 (478) ◽  
pp. 2482-2486
Author(s):  
Takasi TAMARU ◽  
Kazuo SIMODAIRA ◽  
Yoji KUROSAWA ◽  
Hidesi YAMADA ◽  
Tosiyuki KUYAMA
Keyword(s):  
Experimental Investigation ◽  
Gas Turbine ◽  
Gas Turbine Combustor ◽  
Maximum Loading

Experimental investigation on alternative fuel combustion performance using a gas turbine combustor

2019 ◽  
Vol 238 ◽  
pp. 1530-1542 ◽  
Author(s):  
Lukai Zheng ◽  
James Cronly ◽  
Emamode Ubogu ◽  
Ihab Ahmed ◽  
Yang Zhang ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Gas Turbine ◽  
Alternative Fuel ◽  
Fuel Combustion ◽  
Gas Turbine Combustor ◽  
Combustion Performance

Amplitude-Dependent Damping and Driving Rates of High-Frequency Thermoacoustic Oscillations in a Lab-Scale Lean-Premixed Gas Turbine Combustor

2021 ◽  
Author(s):  
Thomas Hofmeister ◽  
Thomas Sattelmayer
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Limit Cycle ◽  
High Frequency ◽  
Mean Flow ◽  
Gas Turbine Combustor ◽  
Cfd Simulations ◽  
The Mean ◽  
Amplitude Dependency ◽  
Thermoacoustic Oscillations

Abstract This paper presents numerical investigations of the amplitude-dependent stability behavior of thermoacoustic oscillations at screech level frequencies in a lean-premixed, swirl-stabilized, lab-scale gas turbine combustor. A hybrid Computational Fluid Dynamics / Computational AeroAcoustics (CFD / CAA) approach is applied to individually compute thermoacoustic damping and driving rates for various acoustic amplitude levels at the combustors' first transversal (T1) eigenfrequency. Forced CFD simulations with the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations mimic the real combustor's rotating T1 eigenmode. An increase of the forcing amplitude over time allows observation of the amplitude-dependent flow field and flame evolution. In accordance with measured OH*-chemiluminescence images, a pulsation amplitude-dependent flame contraction is reproduced in the CFD simulations. At several amplitude levels, period-averaged flow fields are then denoted as reference states, which serve as inputs for the CAA part. There, eigenfrequency simulations with linearized flow equations are performed with the Finite Element Method (FEM). The outcomes are damping and driving rates as a response to the amplitude-dependency of the mean flow field. It is found that driving due to flame-acoustics interactions governs a weak amplitude-dependency, which agrees with experimentally based studies at the authors' institute. This disqualifies the perception of heat release saturation as the root-cause for limit-cycle oscillations in this high-frequency thermoacoustic system. Instead, significantly increased dissipation due to the interaction of acoustically induced vorticity perturbations with the mean flow is identified, which may explain the formation of a limit-cycle.

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