Off-line phase-averaged particle image velocimetry and OH chemiluminescence measurements using acoustic time series

Fischer, André; Bake, Friedrich; Heinze, Johannes; Diers, Olaf; Willert, Christian; Röhle, I.

doi:10.1088/0957-0233/20/7/075403

Cited by 3 publications

(2 citation statements)

References 14 publications

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“…The unsteady chemiluminescence is recorded with a photomultiplier, which images the whole flame. Its signal is used as time reference for the oscillation, the positive zero crossing defined as 0°These time series were the basis for the off-line phase reconstruction [2] of the 2D images of the liquid fuel (Mie scattering) and the reaction zone (OH* chemiluminescence). A laser light sheet was positioned parallel to and 5 mm above the burner face plate, to monitor the Mie scattering from the spray.…”

Section: Diagnosticsmentioning

confidence: 99%

“…As for the laser light sheet measurements for each test case 900 OH* chemiluminescence images were stored for further image processing. After phase averaging using the same method as for the laser light sheets [2], a deconvolution algorithm [3] was applied to the OH* images to deduce phase and spatially resolved images of the heat release. Additionally films of the chemiluminescence were made with a high speed system from an oblique angle.…”

Section: Diagnosticsmentioning

confidence: 99%

See 1 more Smart Citation

Self-Exited Oscillation in a Combustion Chamber Driven by Phase Change in the Liquid Fuel Feed System

Hassa

Heinze²,

Meier³

et al. 2011

International Journal of Spray and Combustion Dynamics

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A new mechanism for the generation of a self-exited oscillation of combustion in a generic combustion chamber typical for aeroengine combustors is described. The cause of the oscillation is the phase change from liquid to vapour which happens when the preheat temperature of the air flowing through the burner exceeds the boiling temperature at the operating pressure and the fuel flow is so low that heat transfer to the liquid fuel causes evaporation within the fuel channels of the burner. Liquid fuel and vapour alternatively enter the airstream of the burner. This leads to an unstable situation for the flame. Measurements of chemiluminescence and liquid fuel show nearly complete extinction and re-ignition for the limit cycle. Prevention of the oscillation is possible by better thermal management of the fuel path.

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Section: Diagnosticsmentioning

confidence: 99%

Section: Diagnosticsmentioning

confidence: 99%

Self-Exited Oscillation in a Combustion Chamber Driven by Phase Change in the Liquid Fuel Feed System

Hassa

Heinze²,

Meier³

et al. 2011

International Journal of Spray and Combustion Dynamics

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Measurements of Density Pulsations in the Outlet Nozzle of a Combustion Chamber by Rayleigh-Scattering Searching Entropy Waves

Rausch

Fischer

Konle

et al. 2010

Journal of Engineering for Gas Turbines and Power

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The development of measurement techniques, which enable temporal and spatial highly resolved density investigations even in harsh environments, is essential. Rayleigh scattering is a noninvasive optical measurement technique permitting such investigations. A Rayleigh-scattering measurement system is set up, providing a new insight into fluid mechanical processes in turbomachines. In this paper, Rayleigh scattering is used for the detection of density oscillations in the optical accessible convergent-divergent outlet nozzle of a small scale combustion test rig at various power consumptions and equivalence ratios. Until now, this part of the combustion chamber is sparsely investigated due to the challenging measurement conditions. The temporal density oscillation inside the nozzle can be shown up to 4 kHz as well as its spatial distribution. Systematic errors of the setup are investigated. Spectra of pressure and density oscillations are compared. Measurements with nonreacting air flow are conducted to study flow induced density fluctuations. Entropy noise related correlations between density and pressure fluctuations are found. Therewith, the builtup Rayleigh-scattering system enables investigations of the presumed region of indirect noise generation.

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Optical Methods for Studies of Self-Excited Oscillations and the Effect of Dampers in a High Pressure Single Sector Combustor

Meier

Lange

Heinze

et al. 2015

Journal of Engineering for Gas Turbines and Power

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Self-excited periodic instabilities in a staged lean burn injector could be forced by operating the combustor at off-design conditions. These pressure oscillations were studied in a high pressure single sector combustor with optical access. Two damper configurations were installed and tested with respect to their damping efficiency in relation to the configuration without dampers. For a variety of test conditions, derived from a part load case, time traces of pressure in the combustor were measured, and amplitudes were derived from their Fourier transformation. These measurements were performed for several combinations of the operating parameters, i.e., injector pressure drop, air/fuel ratio (AFR), pilot/main fuel split, and preheat temperature. These tests “ranked” the respective damper configurations and their individual efficiency with respect to the configuration without dampers. Although a general trend could be observed, the ranking was not strictly consistent for all operating conditions. For several test cases, preferably with pronounced self-excited pressure oscillations, phase-resolved planar optical measurement techniques were applied to investigate the change of spatial structures of fuel, reaction zones, and temperature distributions over a period of an oscillation. A pulsating motion was detected for both pilot and main flame, driven by a pulsating transport of the liquid fuel. This pulsation, in turn, is caused by a fluctuating air velocity, in connection with a prefilming airblast type atomizer. A phase shift between pilot and main injector heat release was observed, corresponding to a shift of fuel penetration. Local Rayleigh indices were calculated qualitatively, based on phase-resolved OH chemiluminescence used as marker for heat release, and corresponding pressure values. This identified regions, where a local amplification of pressure oscillations occurred. These regions were largely identical to the reaction regions of pilot and main injector, whereas the recirculation zone between the injector flows was found to exhibit a damping effect.

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Off-line phase-averaged particle image velocimetry and OH chemiluminescence measurements using acoustic time series

Cited by 3 publications

References 14 publications

Self-Exited Oscillation in a Combustion Chamber Driven by Phase Change in the Liquid Fuel Feed System

Self-Exited Oscillation in a Combustion Chamber Driven by Phase Change in the Liquid Fuel Feed System

Measurements of Density Pulsations in the Outlet Nozzle of a Combustion Chamber by Rayleigh-Scattering Searching Entropy Waves

Optical Methods for Studies of Self-Excited Oscillations and the Effect of Dampers in a High Pressure Single Sector Combustor

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