Investigation of Spray Behavior Downstream of an Aeroengine Injector with Acoustic Excitation

Gajan, Pierre; Strzelecki, Alain; Platet, B.; Lecourt, Renaud; Giuliani, Fabrice

doi:10.2514/1.22394

Cited by 32 publications

(27 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The operating principle of prefilming airblast atomization is the momentum transfer from a high speed gas flow to the liquid phase of a thin film. This type of injector was previously investigated under fluctuating gas velocity conditions [2][3][4][5] and was found to be sensitive to flow fluctuations [4,5]. Consequently, typical spray characteristics such as the droplet flux and the Sauter Mean Diameter might also be influenced by thermoacoustic instabilities.…”

Section: Introductionmentioning

confidence: 99%

Time-Response of Recent Prefilming Airblast Atomization Models in an Oscillating Air Flow Field

Chaussonnet

Müller

Holz

et al. 2017

Journal of Engineering for Gas Turbines and Power

View full text Add to dashboard Cite

The present study investigates the response of recent primary breakup models in the presence of an oscillating air flow, and compares them to an experiment realized by Müller and coworkers in 2008. The experiment showed that the oscillating flow field has a significant influence on the Sauter Mean Diameter (SMD) up to a given frequency. This observation highlights the low-pass filter character of the prefilming airblast atomization phenomenon, which also introduces a significant phase shift on the dynamics of SMD of the generated spray. The models are tested in their original formulations without any calibration in order to assess their robustness versus different experiments in terms of SMD and time-response to an oscillating flow field. Special emphasis is put to identify the advantages and weaknesses of theses models, in order to facilitate their future implementation in CFD codes. It is observed that some models need an additional calibration of the time constant in order to match the time shift observed in the experiment, whereas some others show a good agreement with the experiment without any modification. Finally, it is demonstrated that the low-pass filter character of the breakup phenomenon can be retrieved by considering the history of the local gas velocity, instead of the instantaneous velocity. This might result in a higher simulation fidelity within CFD codes. * geoffroy.chaussonnet@kit.edu † Dr. A. Müller is currently Team leader for sensor systems at JENOPTIK Robot GmbH

show abstract

Section: Introductionmentioning

confidence: 99%

Time-Response of Recent Prefilming Airblast Atomization Models in an Oscillating Air Flow Field

Chaussonnet

Müller

Holz

et al. 2017

Journal of Engineering for Gas Turbines and Power

View full text Add to dashboard Cite

show abstract

“…Like those operated with gaseous fuels, combustors fed by liquid fuels are prone to combustion instabilities triggered by the dynamics of the fuel [1][2][3] or air [1,4,5] supply lines. To determine the stability margins of these non-premixed systems, it is useful to characterize the flame frequency response to external flow perturbations.…”

Section: Introductionmentioning

confidence: 99%

“…For liquid fuel injectors featuring a large pressure drop, thermo-acoustic oscillations result from a resonant coupling with the air feeding line. Analysis of the response of swirl spray flames to air flowrate modulations are generally limited to a few specific forcing frequencies with a fixed amplitude [1,4,8]. It was demonstrated that the oscillation of the air flow leads to droplet clustering [1,7,9] and equivalence ratio fluctuations [6].…”

Section: Introductionmentioning

confidence: 99%

Stability analysis of a swirl spray combustor based on flame describing function

Mirat

Durox

Schuller

2015

Proceedings of the Combustion Institute

View full text Add to dashboard Cite

To cite this version:Clement Mirat, Daniel Durox, Thierry Schuller. Stability analysis of a swirl spray combustor based on flame describing function.Abstract Self-sustained combustion oscillations observed at limit cycles in a swirl combustor equipped with a series of steam assisted liquid fuel injectors are analyzed with the Flame Describing Function (FDF) framework. It is first shown that for globally fuel lean injection conditions, the spray flames investigated burn in a non-premixed mode. A nonsooty and a sooty regime are explored. Their frequency response to acoustic forcing is characterized by exploiting the OH * chemiluminescence signal and a velocity signal measured by Laser Doppler velocimetry at the air injection unit outlet. It is found that the FDF of these non-premixed swirl spray flames features a distinct response compared to lean premixed swirl flames. The gain and phase lag of these FDF are both a strong function of the perturbation amplitude. At a fixed forcing frequency, the FDF phase lag increases with the perturbation level for the non-sooty flame investigated and it decreases for the sooty flame case. The sooty flame has also a much lower cut-off frequency for the FDF gain than the non-sooty flame. It is then shown that these features are essential to reproduce the correct instability bands and oscillation frequencies observed at limit cycles in the experiments. For the sooty flame, combustion is always found stable in agreement with the low cut-off frequency found for the FDF. A linear analysis for the non-sooty flame fails to capture the low frequency instabilities observed in the experiments that have the largest oscillation levels. Only the use of the FDF enables to reproduce the correct dynamical states observed in the combustor. It is further concluded that the OH * chemiluminescence signal may safely be used to infer the frequency response of these non-premixed swirl spray flames at globally fuel lean injection conditions.

show abstract

“…The measured fluctuations are consistent for the M flame, while for the V flame fluctuations are found to be 3 to 4 times higher. One suggestion could be that the acoustic field modulates the flow and the nascent spray inside the injector, resulting in large coherent structures that are generated at the acoustic frequency and convected by the flow [33][34][35][36]. A second suggestion could be that for the V flame, the spray is strongly affected by the presence of the precessing vortex core (PVC) and fluctuations of up to 15% of the mean velocity have been found from the PDA results and PIV fields.…”

Section: -4 / Vol 134 November 2012mentioning

confidence: 99%

Characterization of the Acoustic Interactions in a Two-Stage Multi-Injection Combustor Fed With Liquid Fuel

Providakis¹,

Zimmer²,

Scouflaire³

et al. 2012

Journal of Engineering for Gas Turbines and Power

View full text Add to dashboard Cite

Burners operating in lean premixed prevaporized (LPP) regimes are considered as good candidates to reduce pollutant emissions from gas turbines. Lean combustion regimes result in lower burnt gas temperatures and therefore a reduction on the NO^ emissions, one of the main pollutant species. However, these burners usually show strong flame dynamics, making them prone to various stabilization problems (combustion instabilities, flashback, flame extinction). To face this issue, multi-injection staged combustion can be envisaged. Staging procedures enable fuel distribution control, while multipoint injections can lead to a fast and efficient mixing. A laboratory-scale staged multipoint combustor is developed in the present study, in the framework of LPP combustion, with an injection device dose to the industrial one. Using a staging procedure between the primary pilot stage and the secondary multipoint one, droplet and velocity field distributions can be varied in the spray that is formed at the entrance of the combustion chamber. The resulting spray and flame are characterized using OH-planar laser induced fluorescence, high speed particle image velocimetiy, and phase Doppler anemometry measurements. Three staging values, corresponding to three different flame stabilization processes, are analyzed, while power is kept constant. It is shown that mean values are strongly influenced by the fuel distribution and the flame position. Using adequate postprocessing, the interaction between the acoustic field and the droplet behavior is characterized. Spectral analysis reveals a strong acoustic-flame coupling leading to a low frequency oscillation of both the velocity field and the spray droplet distribution. In addition, acoustic measurements in the feeding line show that a strong oscillation of the acoustic field leads to a change in fuel injection, and hence droplet behavior.

show abstract

Investigation of Spray Behavior Downstream of an Aeroengine Injector with Acoustic Excitation

Cited by 32 publications

References 14 publications

Time-Response of Recent Prefilming Airblast Atomization Models in an Oscillating Air Flow Field

Time-Response of Recent Prefilming Airblast Atomization Models in an Oscillating Air Flow Field

Stability analysis of a swirl spray combustor based on flame describing function

Characterization of the Acoustic Interactions in a Two-Stage Multi-Injection Combustor Fed With Liquid Fuel

Contact Info

Product

Resources

About