Detection of C2 and temperature measurement in a flame by using degenerate four-wave mixing in a forward geometry

Nyholm, K.; Kaivola, Matti; Aminoff, C.G.

doi:10.1016/0030-4018(94)90356-5

Cited by 24 publications

(86 citation statements)

References 11 publications

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“…Since then many molecular and radical species have been detected in flames, cells or high temperature arc sources making use of the discrimination afforded by the coherent signal against flame luminescence or scattering. Important diatomic radical species OH, NH [82,83], CH [84], CN [85] and C 2 [86,87] were detected and used to evaluate the utility of DFWM as a diagnostic technique in flames. Stable combustion product species such as NO [88] and NO 2 [89] which are major atmospheric pollutants were also detected.…”

Section: Molecular Physics Applicationsmentioning

confidence: 99%

“…An alternative and more easily implemented strategy that minimizes beam steering effects is to use the FPG since all beams propagate through approximately similar optical paths. Using this method temperatures were measured using DFWM of C 2 by Nyholm et al [86]. Temporally resolved thermometry requires that the spectral information is obtained within a single laser pulse -a result that is achieved using multiplex or broadband DFWM first demonstrated by Ewart and Snowdon [110].…”

Section: The Potential Of Resonant Dfwm For Thermometry Was Demonstramentioning

confidence: 99%

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Laser diagnostics and minor species detection in combustion using resonant four-wave mixing

Kiefer

Ewart

2011

Progress in Energy and Combustion Science

129

112

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Laser-based methods have transformed combustion diagnostics in the past few decades. The high intensity, coherence, high spectral resolution and frequency tunability available from laser radiation has provided powerful tools for studying microscopic processes and macroscopic phenomena in combustion by linear and nonlinear optical processes. This review focuses on nonlinear optical techniques based on resonant four-wave mixing for non-intrusive measurements of minor species in combustion. The importance of minor species such as reaction intermediates is outlined together with the challenges they present for detection and measurement in the hostile environments of flames, technical combustors, and engines. The limitations of conventional optical methods for such measurements are described and the particular advantages of coherent methods using nonlinear optical techniques are discussed.The basic physics underlying four-wave wave mixing processes and theoretical models for signal calculation are then presented together with a discussion of how combustion parameters may be derived from analysis of signals generated in various four-wave mixing processes. The most important four-wave mixing processes, in this context, are then reviewed:Degenerate Four-Wave Mixing (DFWM), Coherent Anti-Stokes Raman Scattering (CARS), Laser Induced Grating Spectroscopy (LIGS) and Polarization Spectroscopy (PS). In each case the fundamental physics is outlined to explain the particular properties and diagnostic advantages of each technique. The application of the methods mentioned to molecular physics studies of combustion species is then reviewed along with their application in measurement of concentration, temperature and other combustion parameters. Related nonlinear techniques and recent extensions to the ultra-fast regime are briefly reviewed. Finally practical considerations relevant to multi-dimensional and multi-species measurements, as well as applications in technical combustion systems are discussed.Keywords: nonlinear optical spectroscopy, four-wave mixing, combustion diagnostics, minor species detection, laser-induced gratings, polarization spectroscopy IntroductionEnergy from renewable sources such as solar and wind power is the goal of much current research and technological development. Combustion, however, is and is likely to remain for the foreseeable future, the most important energy source for heat, electrical power and especially for transportation. In technical combustion systems the chemical energy of fossil fuels such as coal, crude oil and natural gas is converted into heat through oxidation with oxygen from air. However, fossil fuel resources are limited and alternatives like biofuels [1] or novel technologies such as fuel cells [2] are not yet able to meet the demand. Consequently, for a sustainable use of fossil fuels it is desirable to further improve the efficiency, maintainability and reliability of existing combustion devices. Achieving such improvements depends upon an improved understanding of t...

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Section: Molecular Physics Applicationsmentioning

confidence: 99%

Section: The Potential Of Resonant Dfwm For Thermometry Was Demonstramentioning

confidence: 99%

Laser diagnostics and minor species detection in combustion using resonant four-wave mixing

Kiefer

Ewart

2011

Progress in Energy and Combustion Science

129

112

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“…2 depicts the wavelength region of the (4, 3) band of the d 3 P g À a 3 P u system. In addition transitions appear in this range that are due to other sequence bands such as (5,4) and (6,5). The bands are denoted by the standard nomenclature ðv 0 ; v 00 Þ.…”

Section: Resultsmentioning

confidence: 99%

“…The strong d 3 P g À a 3 P u electronic system has been used to detect this minor species in combustion processes by applying numerous experimental techniques such as laser-induced fluorescence (LIF) [1][2][3], chemiluminescence [1], degenerate four-wave mixing (DFWM) [4,5], cavity ring-down (CRD) [2,6,7] and intracavity laser absorption spectroscopy (ICL) [8]. In addition, a recent experiment reports on the application of polarization spectroscopy of C 2 to visualize soot formation [9] and LIF for soot volume fraction measurements [10].…”

Section: Introductionmentioning

confidence: 99%

Deperturbation study of the state of C2 by applying degenerate and two-color resonant four-wave mixing

Bornhauser

Knopp

Gerber

et al. 2010

Journal of Molecular Spectroscopy

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“…3,4 It has been shown that the technique is useful for atoms as well as for molecules like NO, 1 OH, 2 CH, 5 C 2 , 6 and NH 3 . 7 Like other coherent techniques as for example resonance enhanced coherent anti-Stokes Raman scattering ͑RECARS͒, 8 it combines high resolution with high sensitivity down to 10 9 particles per quantum state and cm 3 .…”

mentioning

confidence: 99%

Temperature determination of transient species by degenerate four wave mixing: Application of the independently determined power law of the transition dipole moment and geometric factors

Lehr

Motzkus

Pichler

et al. 1996

The Journal of Chemical Physics

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We investigated the dependence of the degenerate four wave mixing ͑DFWM͒ signal intensities on the electronic transition dipole moment of isolated lines in the A 1 ⌺ ϩ ←X 1 ⌺ ϩ transition band of NaH. We applied a new method to determine this dependence in transient species without previous knowledge of the sample temperature. By using different appropriate pairs of DFWM lines sharing common lower level, the relative population difference is eliminated. We found that this ratio is well described by a power law ( 1 / 2 ) x where i is the electronic one-photon transition dipole moment. As a result of saturation the exponent x depends on the total laser energy deposited in the medium. The observations are in good agreement with a modified two-level model, which includes the effects of polarization of the laser beams used in the experimental setup by introducing geometric factors. The exponent of the integrated signal intensities varies between 3 and 8 for high and low laser intensities with a rapid decrease to high intensities. This makes it possible to compare signal intensities at different DFWM laser intensities in order to obtain relative level populations, i.e., temperature, with high sensitivity.

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Detection of C2 and temperature measurement in a flame by using degenerate four-wave mixing in a forward geometry

Cited by 24 publications

References 11 publications

Laser diagnostics and minor species detection in combustion using resonant four-wave mixing

Laser diagnostics and minor species detection in combustion using resonant four-wave mixing

Deperturbation study of the state of C2 by applying degenerate and two-color resonant four-wave mixing

Temperature determination of transient species by degenerate four wave mixing: Application of the independently determined power law of the transition dipole moment and geometric factors

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