Efficient Acoustic Modal Analysis for Industrial CFD

Caraeni, Mirela; Devaki, Ravi; Aroni, Matteo; Oswald, Marco; Srikanth, Kvss; Caraeni, Doru

doi:10.2514/6.2009-1418

Cited by 3 publications

(2 citation statements)

References 9 publications

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“…The signatures of a blowout condition can be recognized in localized extinction and reignition events and irregular rates of fuel consumption. In more detail, unstable combustion is related to self-sustained combustion oscillations at or near the acoustic frequency of the combustion chamber, which are the result of the closed loop coupling between unsteady heat release and pressure fluctuations [ 3 , 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

Ion Current Sensor for Gas Turbine Condition Dynamical Monitoring: Modeling and Characterization

Addabbo

Fort

Landi

et al. 2021

Sensors

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This paper aims to thoroughly investigate the potential of ion current measurements in the context of combustion process monitoring in gas turbines. The study is targeted at characterizing the dynamic behavior of a typical ion-current measurement system based on a spark-plug. Starting from the preliminary study published in a previous work, the authors propose a refined model of the electrode (spark plug), based on the Langmuir probe theory, that incorporates the physical surface effects and proposes an optimized design of the conditioning electronics, which exploits a low frequency AC square wave biasing of the electrodes and allows for compensating some relevant parasitic effects. The authors present experimental results obtained in the laboratory, which allow for the evaluation of the validity of the model and the interpreting of the characteristics of the measurement signal. Finally, measurements carried out in the field on an industrial combustor are presented. The results confirm that the charged chemical species density sensed by the proposed measurement system and related to the mean value of the output signal is an indicator of the ‘average’ combustion process conditions in terms e.g., of air/fuel ratio, whereas the high frequency spectral component of the measured signal can give information related to the turbulent regime and to the presence of pressure pulsations. Results obtained with a prototype system demonstrated an achievable resolution of about 5 Pa on the estimated amplitude, even under small biasing voltage (22.5 V) and an estimated bandwidth of 10 kHz.

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Section: Introductionmentioning

confidence: 99%

Ion Current Sensor for Gas Turbine Condition Dynamical Monitoring: Modeling and Characterization

Addabbo

Fort

Landi

et al. 2021

Sensors

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“…A popular strategy for predicting instabilities involves the splitting of the phenomenon into processes related to the acoustic field and processes related to the flow field and flame (Noiray, Durox, Schuller, and Candel (2008)). The acoustic field may be resolved using a number of non-linear (Caraeni, Devaki, Aroni, Oswald, and Caraeni (2009)), linearised (Nicoud, Benoit, Sensiau, and Poinsot (2007)) or semianalytical acoustic network models (Dowling and Stow (2003)) which require as their input a flame transfer function (FTF) which links heat release fluctuations of the flame with velocity, pressure, or mass flow rate fluctuations at a reference point inside the combustion chamber. The FTF can be derived using experimental methods or using large eddy simulation (LES) (see for instance : Candel, Durox, Schuller, Bourgouin, and Moeck (2014), Chong, Komarek, Kaess, Foller, and Polifke (2010), Palies, Schuller, Durox, Gicquel, and Candel (2011), Dupuy et al (2020) and Merk et al (2019)).…”

Section: Introductionmentioning

confidence: 99%

The Effects of Turbulence on Jet Stability and the Flame Transfer Function in a Lean-burn Combustor

Treleaven

Garmory

Page

2020

Combustion Science and Technology

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Large eddy simulations show that the penetration of the central jet in a multipassage lean burn and liquid fuelled combustor is dependent on the turbulence levels in the three air-flow passages of the injector. These simulations are performed using an incompressible method where an unsteady boundary condition is applied to the inlets of a truncated domain which only includes the domain downstream of the fuel injector using the recently developed Proper Orthogonal Decomposition Fourier Series method. The fluctuating inlets are built from a combination of compressible URANS data and incompressible LES data. This incompressible method is shown to be consistent with fully compressible simulations whilst requiring only one third of the computing time. Neglecting the turbulence generated in the passages results in the incorrect penetration of the central jet, resulting in a flame transfer function with a similar gain but with a different phase. Furthermore, large scale helical modes, previously detected in non-reacting simulations of a similar burner geometry are seen to be imprinted onto the liquid fuel spray, mixture fraction and heat release fields. This shows that coupling between hydrodynamic instabilities and thermoacoustic instabilities in liquid fuelled engines may be more significant than suggested by previous studies of gas fuelled engines.

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Parallelization Strategies for Computational Fluid Dynamics Software: State of the Art Review

Afzal¹,

Ansari²,

Faizabadi³

et al. 2016

Arch Computat Methods Eng

122

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Efficient Acoustic Modal Analysis for Industrial CFD

Cited by 3 publications

References 9 publications

Ion Current Sensor for Gas Turbine Condition Dynamical Monitoring: Modeling and Characterization

Ion Current Sensor for Gas Turbine Condition Dynamical Monitoring: Modeling and Characterization

The Effects of Turbulence on Jet Stability and the Flame Transfer Function in a Lean-burn Combustor

Parallelization Strategies for Computational Fluid Dynamics Software: State of the Art Review

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