Flame Spectra of a Turbulent Liquid-Fueled Swirl-Stabilized Lean-Direct Injection Combustor

Yi, Tongxun; Santavicca, Domenic A.

doi:10.2514/1.43003

Cited by 20 publications

(6 citation statements)

References 24 publications

(33 reference statements)

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“…Until now, the relationship between the ratio of different chemiluminescence signals and the equivalence ratio for liquid fuelled flames has not been widely investigated. Yi and Santavicca (2009) studied the spectrum of a turbulent swirl-stabilized flame using Jet A1 as fuel. They reported the spectrum of the liquid fuelled combustor to be very similar to that of lean premixed gaseous combustion.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of equivalence ratio fluctuations in a lean premixed kerosene combustor

et al. 2021

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In this study a measurement technique for determination of equivalence ratio fluctuations from flame chemiluminescence in a kerosene-fuelled lean premixed combustor under atmospheric conditions is presented. Firstly, fundamental investigations into the relationship between the ratio of different chemiluminescence signals and the equivalence ratio are carried out using an imaging spectrometer. The chemiluminescence intensity is recorded for a wide range of equivalence ratios and fuel mass flows during steady state operation. The spectra show that the CH*/OH* ratio depends linearly on the equivalence ratio and is independent of the mass flow in the investigated range. Moreover, the background radiation has no influence on the monotonous trend of the CH*/OH* ratio for kerosene combustion. This interesting finding opens up new possibilities for passive optical measurement of the equivalence ratio in kerosene flames. Bandpass-filtered phase-correlated images of OH* and CH* chemiluminescence of an acoustically excited flame are taken simultaneously on one camera chip using an image doubler. After distortion correction, the image pair is used to calculate the global equivalence ratio from the CH*/OH* ratio. Based on the calibration chart derived in stationary operation, phase-resolved equivalence ratio perturbations are determined during acoustic excitation. The presented technique allows a quantitative measurement of equivalence ratio fluctuations in spray combustion and can therefore provide a better understanding of the fundamental mechanisms of thermoacoustic instabilities triggered by equivalence ratio fluctuations. Graphic abstract

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Section: Introductionmentioning

confidence: 99%

Experimental investigation of equivalence ratio fluctuations in a lean premixed kerosene combustor

et al. 2021

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“…Yi and Santavicca. 16–18 studied a Jet-A fueled combustor at moderately higher pressure (0.3 MPa) and found pressure fluctuations amplitudes as high as 8% of the mean chamber pressure with longitudinal mode frequencies of 371 Hz (1L), 699 Hz, and 1400 Hz. Dependencies of equivalence ratio, incoming air flow rate and air temperature on instability amplitudes were reported, with higher equivalence ratio and lower air flow rate and temperature being more unstable.…”

Section: Introductionmentioning

confidence: 99%

Parametric investigation of combustion instabilities in a single-element lean direct injection combustor

Gejji

Huang

Fugger

et al. 2018

International Journal of Spray and Combustion Dynamics

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Self-excited combustion dynamics in a liquid-fueled lean direct injection combustor at high pressure (1 MPa) are described. Studied variables include combustor and air plenum length, inlet air temperature, equivalence ratio, fuel nozzle location, and fuel composition. Measured pressure oscillations were dependent on combustor geometry and ranged from about 1% of mean chamber pressure at low equivalence ratio, up to 20% at high equivalence ratio. In the most unstable cases, strong pressure modes were measured throughout the frequency spectrum including a band around 1.2-1.5 kHz representing the 4th longitudinal mode, and another band around 7 kHz. The oscillation amplitudes have a non-monotonic dependency on air temperature, and are affected by the placement of the fuel nozzle relative to the throat of the subsonic swirling air flow. The parametric survey provides a rich dataset suitable for validating high-fidelity simulations and their subsequent use in analyzing and interpreting the complex combustion dynamics.

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“…The trends of these species can be considered as a marker of the combustion status as well as of LBO limit [17,18]. A high acquisition rate is crucial to analyze the dynamic phenomena typical of the lean flame [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

“…However only a few studies have investigated flame blowout in presence of a lean liquid fueled combustor [19,[24][25][26], which is characterized by unique processes such as atomization and evaporation not involved in gas combustion.…”

Section: Introductionmentioning

confidence: 99%

“…Yi and Santavicca [19] investigated both the flame structure and the combustion instability characteristics in a turbulent liquid-fueled swirl-stabilized lean direct fuel injection combustor. The imaging of CH* chemiluminescence measurements showed that during combustion instability there are mainly variations in the chemiluminescence intensity rather than in the spatial distribution of heat release.…”

Section: Introductionmentioning

confidence: 99%

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Pollutant Formation during the Occurrence of Flame Instabilities under Very-Lean Combustion Conditions in a Liquid-Fuel Burner

et al. 2017

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Recent advances in gas turbine combustor design are aimed at achieving low exhaust emissions, hence modern aircraft jet engines are designed with lean-burn combustion systems. In the present work, we report an experimental study on lean combustion in a liquid fuel burner, operated under a non-premixed (single point injection) regime that mimics the combustion in a modern aircraft engine. The flame behavior was investigated in proximity of the blow-out limit by an intensified high rate Charge-Coupled Device (CCD) camera equipped with different optical filters to selectively record single species chemiluminescence emissions (e.g., OH*, CH*). Analogous filters were also used in combination with photomultiplier (PMT) tubes. Furthermore this work investigates well-mixed lean low NO x combustion where mixing is good and generation of solid carbon particulate emissions should be very low. An analysis of pollutants such as fine particles and gaseous emissions was also performed. Particle number concentrations and size distributions were measured at the exhaust of the combustion chamber by two different particle size measuring instruments: a scanning mobility particle sizer (SMPS) and an Electrical Low Pressure Impactor (ELPI). NO x concentration measurements were performed by using a cross-flow modulation chemiluminescence detection system; CO concentration emissions were acquired with a Cross-flow modulation Non-dispersive infrared (NDIR) absorption method. All the measurements were completed by diagnostics of the fundamental combustor parameters. The results herein presented show that at very-lean conditions the emissions of both particulate matter and CO was found to increase most likely due to the occurrence of flame instabilities while the NO x were observed to reduce.

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Flame Spectra of a Turbulent Liquid-Fueled Swirl-Stabilized Lean-Direct Injection Combustor

Cited by 20 publications

References 24 publications

Experimental investigation of equivalence ratio fluctuations in a lean premixed kerosene combustor

Experimental investigation of equivalence ratio fluctuations in a lean premixed kerosene combustor

Parametric investigation of combustion instabilities in a single-element lean direct injection combustor

Pollutant Formation during the Occurrence of Flame Instabilities under Very-Lean Combustion Conditions in a Liquid-Fuel Burner

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