Structure of a spray flame stabilized on a production engine combustor swirl CUP

Takahashi, Fumika; Schmoll, W. J.; Switzer, G.; Shouse, Dale T.

doi:10.1016/s0082-0784(06)80643-0

Cited by 10 publications

(2 citation statements)

References 11 publications

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“…Laser interferometric techniques have already been extensively used in such environments for the characterization of the dispersed phase, as is also the case for the present study. On the other hand, laser spectroscopic techniques, that are virtually irreplaceable for temperature and species measurements in a turbulent environment, have been adapted only very recently to combusting sprays (Takahashi et al 1996;Luczak et al 1996), in some case through developments in our own laboratory (Karpetis & Gomez 1996). Consequently, this is the first study in which both types of diagnostic techniques, specifically Phase Doppler interferometry and spontaneous Raman scattering thermometry, are applied quantitatively in the same spray combustion system.…”

Section: Introductionmentioning

confidence: 99%

Self-similarity, momentum scaling and Reynolds stress in non-premixed turbulent spray flames

Karpetis

Gomez

1999

J. Fluid Mech.

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An experimental study was conducted in a turbulent spray flame in which droplets were produced ultrasonically at low velocity relative to the host gas. In this fashion, injector-specific effects on the two-phase flow were minimized and a scenario generally characteristic of the far field of practical spray systems could be simulated. Close to the burner exit, the spray flame appeared as a dense column of drops burning with an envelope flame. Further downstream, it opened up slowly in the radial direction and developed a turbulent ‘brush’ appearance. Measurements of the size, velocity and concentration of the droplets, and of gas-phase velocity and temperature were made by combining a Phase-Doppler interferometric technique with Stokes/anti-Stokes Raman thermometry. The experimental data were used to derive scaling and self-similarity for the Reynolds-averaged continuity and momentum equations using suitable transformations.Results showed three distinct regions, on the basis of the behaviour of the gas axial velocity in the spray flame. In the lower part of the flame, the gas momentum increased because of vaporization. In the intermediate region of the spray flame, the axial velocity decayed along the centreline as an inverse power of the distance from the virtual origin, with exponents smaller than unity. In the upper part of the spray flame, the flow field recovered the axial velocity decay that is typical of incompressible jets, namely as an inverse of the axial distance. Self-similar behaviour held for the axial velocity throughout the intermediate region. The vapour source term in the gas continuity equation scaled approximately as an inverse power of axial distance, and exhibited self-similarity throughout the spray flame. As a result, a simple model of the Reynolds stress term could be formulated, in which two competing contributions appear: one, that is due to turbulent transport, tends to increase the value of the velocity correlation; another, that is due to the vaporization term, tends to reduce the value of the velocity correlation and can be construed as a vaporization-induced tendency towards relaminarization. The first term is modelled by a classic gradient-transport approach yielding an empirical mixing length relating the velocity correlation to the average velocity gradient. Model and experiments are found to be in good agreement, especially sufficiently far from the injector, where one-way coupling between the two phases holds.

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Section: Introductionmentioning

confidence: 99%

Self-similarity, momentum scaling and Reynolds stress in non-premixed turbulent spray flames

Karpetis

Gomez

1999

J. Fluid Mech.

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“…In a previous study of this injector, measure-laser is doubled to obtain a tunable UV laser beam for ments of the velocity and size distribution of fuel exciting laser-induced fluorescence. The dye laser is 9 inverted hollow cone with recirculation zones on the configured with Rhodamine 590 dye and a Bethune-cell amplifier, which provides a circular beam profile. Turning prisms relay the UV beam to the combustor facility, where the beam is expanded and formed into a sheet.…”

Section: Introductionmentioning

confidence: 99%

Imaging of laser-induced fluorescence in a high-pressure combustor

Frank

Miller

Allen

1999

37th Aerospace Sciences Meeting and Exhibit

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Recently, we have completed the development of anThe ability to obtain quantitative planar laser-incorporates a production fuel injector and is capable of induced fluorescence (PLIF) measurements in a high-operating at pressures up to 50 atm with preheated air. pressure combustor would represent a significant This facility allows laser-based imaging techniques to be advance in the application of laser diagnostics to prac-performed at conditions that are representative of gastical combustion systems. To simulate the combustion turbine combustors. environment of a gas-turbine engine, an opticallyaccessible high-pressure combustor has been con-Planar laser-induced fluorescence (PLIF) is a widely structed. The combustor facility incorporates a pro-used diagnostic technique capable of providing instanduction liquid-fuel injector and a preheated air supply.taneous two-dimensional measurements in flames. In this paper, we demonstrate the feasibility of instan-However, the application of PLIF techniques to practical taneous OH PLIF measurements in spray flames of combustion devices operated at high pressure remains a heptane and Jet-A fuel at pressures up to 20 atm. Obser-challenge. Examples of such applications include PLIF vations of OH PLIF images at a range of pressures and imaging of fuel concentration in a flame-tube and a overall equivalence ratios are presented.spark-ignition engine. PLIF measurements of OH and

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Temperature and CO2 concentration measurements in the exhaust stream of a liquid-fueled combustor using dual-pump coherent anti-Stokes Raman scattering (CARS) spectroscopy

Roy

Meyer

Lucht

et al. 2004

Combustion and Flame

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Structure of a spray flame stabilized on a production engine combustor swirl CUP

Cited by 10 publications

References 11 publications

Self-similarity, momentum scaling and Reynolds stress in non-premixed turbulent spray flames

Self-similarity, momentum scaling and Reynolds stress in non-premixed turbulent spray flames

Imaging of laser-induced fluorescence in a high-pressure combustor

Temperature and CO2 concentration measurements in the exhaust stream of a liquid-fueled combustor using dual-pump coherent anti-Stokes Raman scattering (CARS) spectroscopy

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