Vortex-shedding and mixing layer effects on periodic flashback in a lean premixed prevaporized gas turbine combustor

Dhanuka, Sulabh K.; Temme, Jacob; Driscoll, James F.; Mongia, H. C.

doi:10.1016/j.proci.2008.06.155

Cited by 117 publications

(40 citation statements)

References 30 publications

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“…This structure is caused by the lip vortex and some of the burned gas is trapped in this region. The existence of the lip recirculation zone (LRZ, [2]) was confirmed by our previous PIV measurements [13,14]. For further low AFR p cases (not shown), the location with OH-LIF signals in zone (iii) further moves towards outside with decreasing its intensity, as the mixture downstream of the injector becomes too rich.…”

Section: Resultssupporting

confidence: 74%

“…For reduction of NOx from aircrafts, coaxial-staging lean burn fuel injection systems have been studied intensively these days [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] and some of them have been already in service. Typically, they consist of a non-premixedmode pilot nozzle at the center for flame stability and a lean premixed-mode main nozzle surrounding the pilot for drastic NOx reductions.…”

Section: Introductionmentioning

confidence: 99%

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Visualization of pilot flame of an optically-accessible coaxially-staged aero-engine lean-burn fuel injector

Matsuura

Uesaka

Iwasaki

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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The visualization of the pilot flame of a coaxially-staged aero-engine lean-burn fuel injector, not only downstream but also inside of the pilot nozzle, was successfully performed at realistic aero-engine conditions. Optical access toward the inside of the nozzle was achieved through the inner and outer shrouds, both of which were made of transparent quartz. The image distortion caused by complex contours of the two shrouds was corrected by a method based on optical ray tracing, which realized precise determination of spatial intensity distribution of optical signals. Line-of-sight OH chemiluminescence, cross-sectional OH-LIF, kerosene LIF and kerosene Mie scattering were employed as diagnostic tools. The effects of pilot local air-to-fuel ratio on spray flame structure were revealed, both inside and downstream of the pilot nozzle under stable combustions. As the pilot mixture got rich, the main reaction zone moved from inside of the pilot nozzle to the region near the injector lip downstream of the injector exit. The OH-LIF signal was detected near the central axis surrounded by the fuel spray. It was also observed near the back-step of the pilot nozzle for the rich cases. The experiments under combustion oscillation were also conducted and the correlation of phenomena inside and downstream of the pilot nozzle was captured. It was clarified that the reaction enhancement in the outer part of the lip vortex region was caused by the convection of rich mixture, which appeared near the pilot atomizer lip at 150~210deg earlier oscillation phase angle. KeywordsAero-engine combustor, Optical burner/injector, Staged lean-burn injector, Laser induced fluorescence, Ray tracing, Optical refraction correction, Elevated temperature and pressure IntroductionFor reduction of NOx from aircrafts, coaxial-staging lean burn fuel injection systems have been studied intensively these days [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] and some of them have been already in service. Typically, they consist of a non-premixedmode pilot nozzle at the center for flame stability and a lean premixed-mode main nozzle surrounding the pilot for drastic NOx reductions. For such an injector, both fuel injection and fuel/air mixing start a few centimeter upstream from the injector exit (i.e. entrance of the combustion chamber). Moreover, this is also true for its pilot flame. Therefore, many important phenomena take place in regions enclosed by the metal walls of the injector, where the application of optical diagnostics is not straightforward compared with a conventional combustor. In our previous work, visualization of fuel spray/vapor behavior and fuel/air mixing inside the main nozzle (i.e. the premixing duct) was performed by high speed visualization and/or LIF techniques [10,11,15]. Through a fullycontoured quartz-made transparent outer-shroud, dynamic motion of fuel sprays under combustion oscillations at an elevated pressure and temperature was clearly captured and discussed in relation to the flame dynamics downstream [15]. ...

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Section: Resultssupporting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Visualization of pilot flame of an optically-accessible coaxially-staged aero-engine lean-burn fuel injector

Matsuura

Uesaka

Iwasaki

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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“…These instabilities arise from coupling between heat release, pressure, and flow oscillations, and so understanding the velocity field dynamics is important for determining coupling mechanisms. Other important GTC phenomena that are linked to the velocity field include blow-off, flashback, and ignition (Knole and Sattelmayaer, 2009;Dhanuka et al, 2009;Littlejohn and Cheng, 2007). Accurate velocity field measurements are challenging in GTCs, particularly temporally resolved (i.e.…”

mentioning

confidence: 99%

Development and evaluation of gappy-POD as a data reconstruction technique for noisy PIV measurements in gas turbine combustors

2016

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How to cite TSpace itemsAlways cite the published version, so the author(s) will receive recognition through services that track citation counts, e.g. Scopus. If you need to cite the page number of the author manuscript from TSpace because you cannot access the published version, then cite the TSpace version in addition to the published version using the permanent URI (handle) found on the record page.This article was made openly accessible by U of T Faculty. Please tell us how this access benefits you. Your story matters. Experiments in Fluids manuscript No. (will be inserted by the editor)Development and evaluation of Gappy-POD as a data reconstruction technique for noisy PIV measurements in gas turbine combustorsReceived: date / Accepted: date Abstract Low signal-to-noise in particle image velocimetry (PIV) measurements in systems such as high pressure gas turbine combustors can result in significant data gaps that negatively affect subsequent analysis. Here, gappy proper orthogonal decomposition (GPOD) is evaluated as a method of filling such missing data. Four GPOD methods are studied, including a new method that utilizes a median filter (MF) to adaptively select whether a local missing data point is updated with a new guess at each iteration. These methods also are compared against local Kriging interpolation. The GPOD methods are tested using PIV data without missing vectors that were obtained in atmospheric pressure swirl flames. Parameters studied include the turbulence intensity, amount of missing data, and he amount of noise in the valid data. Two criteria to check for GPOD convergence also were investigated.The MF method filled in the missing data with the lowest error across all parameters tested, with approximately one-third the computational cost of Kriging. Furthermore, the accuracy of MF GPOD was relatively insensitive to the quality of the convergence criterion. Therefore, compared to the three other GPOD methods and Kriging interpolation, the MF GPOD method is an effective method for filling missing data in PIV measurements in the current gas turbine combustor flows.

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“…Premixing allows careful control over the local flame temperatures in the combustion zone to avoid any potential Nox-forming hotspots Lean Premixed Prevaporized combustors can cause a drastic reduction in Nox emissions. However, their lean flammability limit is narrow and they tend to cause flashbacks, depending on the fuel concentration and flow velocity, compared with the commonly used diffusive combustion method [20][21][22].…”

Section: Lean Premixed Prevaporized (Lpp) Combustionmentioning

confidence: 99%

Most effective combustion technologies for reducing Nox emissions in aero gas turbines

Ommi¹,

Azimi²

2012

The International Journal of Multiphysics

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Vortex-shedding and mixing layer effects on periodic flashback in a lean premixed prevaporized gas turbine combustor

Cited by 117 publications

References 30 publications

Visualization of pilot flame of an optically-accessible coaxially-staged aero-engine lean-burn fuel injector

Visualization of pilot flame of an optically-accessible coaxially-staged aero-engine lean-burn fuel injector

Development and evaluation of gappy-POD as a data reconstruction technique for noisy PIV measurements in gas turbine combustors

Most effective combustion technologies for reducing Nox emissions in aero gas turbines

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