Laser in situ monitoring of combustion processes

Arnold, A.; Becker, Hans; Hemberger, R.; Hentschel, W.; Ketterle, Wolfgang; Köllner, Malte; Meienburg, W.; Monkhouse, P.; Neckel, H.; Schäfer, M.; Schindler, K.-P.; Sick, Volker; Suntz, Rainer; Wolfrum, J.

doi:10.1364/ao.29.004860

Cited by 41 publications

(4 citation statements)

References 32 publications

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“…The observed fluorescence around 297 nm corresponds to the (3 − 2) band. The population of the J = 8 level in connection with the strong P1(8) line in the tuning range of the KrF* excimer laser shows only a minor dependency on the temperature in a range between 1300 and 3100 K [29]. Hence the advantage of this detection scheme is the temperature insensitiveness of the OH fluorescence signal in the expected temperature range.…”

Section: Planar Laser-induced Fluorescence Of Ohmentioning

confidence: 93%

Experimental Study on Stabilization of Lifted Swirl Flames in a Model GT Combustor

Janus

Dreizler

Janicka

2005

Flow Turbulence Combust

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This study reports on experimental investigations on isothermal and reacting swirled nonpremixed flows under varying pressure conditions. In this configuration, a central high speed fuel jet was surrounded by a heated swirling air flow. For the reacting case natural gas served as fuel whereas for isothermal conditions fuel was replaced by a mixture of helium and air to achieve Reynoldssimilarity. The optically accessible combustor allowed for application of laser diagnostics. Here we report on Laser Doppler Anemometry and planar laser-induced fluorescence (PLIF) experiments used to characterize the flow field and visualize selected scalars, respectively. Acetone served as a fluorescence marker for mixture fraction investigations. The hydroxyl radical was used to provide general features of the reaction zone such as flame shape and mean stabilization. To expose the influence of pressure on the flame structure three different operating points were investigated varying the combustor pressure between 2 and 6 bar while the inflow bulk velocities remained the same. Striking features of the present configuration are a detached flame, multiple recirculation zones, and complex coherent flow structures.

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Section: Planar Laser-induced Fluorescence Of Ohmentioning

confidence: 93%

Experimental Study on Stabilization of Lifted Swirl Flames in a Model GT Combustor

Janus

Dreizler

Janicka

2005

Flow Turbulence Combust

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“…Typically, levels with not too different predissociation lifetimes [23,37] are excited (e.g. P, (8) or P,(8) and Q 1 ( l l ) or Q2(ll) [4,38]. Evaluating sequcntially measured averaged 2D fluorescence distributions in a laminar flame, this approach [38] was substan-tially more successful than that of Ref.…”

Section: Temperature Measurementmentioning

confidence: 99%

Two‐Dimensional LIF Approaches for the Accurate Determination of Radical Concentrations and Temperature in Combustion

Meier¹,

Kienle²,

Plath³

et al. 1992

Ber Bunsenges Phys Chem

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Fluorescence RadicalsLaser-induced fluorescence (LIF) techniques for the quantitative, point-wise measurement of radical concentrations and temperature were developed and applied in laboratory-scale combustion systems. Currcntly, the potential of similar measurement strategies for accurate two-dimensional, single-pulse experiments is being investigated. The sensitivity of typical LIF approaches for the determination of temperature and concentration to several parameters, especially to collision processes, is examined. Instantaneous two-dimensional two-species fluorescence imaging is demonstrated in a turbulent H2 diffusion flame. Implications for the quantitative interpretation of these results are discussed in view of single-pulse multi-species spontaneous Raman measurements under similar conditions.

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“…More modest absorption lengths are provided by nonresonant devices such as integrated cavity output (ICO) [5,6] and ringdown (ICRD) [7] spectroscopies as well as various multipass absorption spectroscopies (MPAS) [8][9][10][11][12][13]. The nonresonant methods are simple to work with and more robust against misalignment and have so far achieved path length of up to about 240 m. Multipass absorption cells have been used in applications including environmental monitoring [14][15][16][17], analyses of combustion processes [18,19], performance of medical diagnostics [20], and the study of fundamental atomic and molecular physics [21,22].…”

Section: Introductionmentioning

confidence: 99%

Multipass cell based on confocal mirrors for sensitive broadband laser spectroscopy in the near infrared

et al. 2013

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We report on broadband absorption spectroscopy in the near IR using a multipass cell design based on highly reflecting mirrors in a confocal arrangement having the particular aim of achieving long optical paths. We demonstrate a path length of 314 m in a cell consisting of two sets of highly reflecting mirrors with identical focal length, spaced 0.5 m apart. The multipass cell covers this path length in a relatively small volume of 1.25 l with the light beam sampling the whole volume. In a first application, the absorption spectra of the greenhouse gases CO(2), CH(4), and CO were measured. In these measurements we used a femtosecond fiber laser with a broadband spectral range spanning the near IR from 1.5 to 1.7 μm. The absorption spectra show a high signal-to-noise ratio, from which we derive a sensitivity limit of 6 ppmv for methane observed in a mixture with air.

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Laser in situ monitoring of combustion processes

Cited by 41 publications

References 32 publications

Experimental Study on Stabilization of Lifted Swirl Flames in a Model GT Combustor

Experimental Study on Stabilization of Lifted Swirl Flames in a Model GT Combustor

Two‐Dimensional LIF Approaches for the Accurate Determination of Radical Concentrations and Temperature in Combustion

Multipass cell based on confocal mirrors for sensitive broadband laser spectroscopy in the near infrared

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