WIDECARS spectra fitting in a premixed ethylene–air flame

Cutler, Andrew D.; Gallo, Emanuela; Cantu, Luca

doi:10.1002/jrs.4829

Cited by 13 publications

(9 citation statements)

References 17 publications

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“…Logarithmic and square-root transformation have been used previously in the literature for similar reasons. [4,10,12] The z-score transformation subtracts off parameter means and divides by the standard deviation. This is done separately for each of the five parameters and helps standardize the potentially disparate scales of different parameters.…”

Section: Application On a Simulated Flowmentioning

confidence: 99%

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Adaptive modeling powers fast multiparameter fitting of CARS spectra

Hunt

Ground

Cutler

2022

J Raman Spectroscopy

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Coherent anti‐Stokes Raman Spectroscopy (CARS) is a laser‐based measurement technique widely applied across many science and engineering disciplines to perform non‐intrusive gas diagnostics. CARS is often used to study combustion, where the measured spectra can be used to simultaneously recover multiple flow parameters from the reacting gas such as temperature and relative species mole fractions. This is typically done by using numerical optimization to find the flow parameters for which a theoretical model of the CARS spectra best matches the actual measurements. The most commonly used theoretical model is the CARSFT spectrum calculator. Unfortunately, this CARSFT spectrum generator is computationally expensive, and using it to recover multiple flow parameters can be prohibitively time‐consuming, especially when experiments have hundreds or thousands of measurements distributed over time or space. To overcome these issues, several methods have been developed to approximate CARSFT using a library of pre‐computed theoretical spectra. In this work, we present a new approach that leverages ideas from the machine learning literature to build an adaptively smoothed kernel‐based approximator. In application on a simulated dual‐pump CARS experiment probing a H2/air flame, we show that the approach can use a small number library spectra to quickly and accurately recover temperature and four gas species' mole fractions. The method's flexibility allows fine‐tuned navigation of the trade‐off between speed and accuracy and makes the approach suitable for a wide range of problems and flow regimes.

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Section: Application On a Simulated Flowmentioning

confidence: 99%

“…The goal is to use this library to approximate the relationship between flow parameters and their corresponding spectra. The most common approach is to fit multivariate interpolating Lagrange polynomials [1,6,10,12] …”

Section: Introductionmentioning

confidence: 99%

Adaptive modeling powers fast multiparameter fitting of CARS spectra

Hunt

Ground

Cutler

2022

J Raman Spectroscopy

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“…The technique was demonstrated in the analysis of experimental measurements in an equivalence ratio 2:1 ethylene‐air flame above the surface of a McKenna burner. Precision errors because of experimental and fitting effects were discussed . Dennis et al carried out high dynamic‐range thermometry at 5 kHz in hydrogen‐air diffusion flame using chirped‐probe‐pulse femtosecond CARS scattering.…”

Section: Non‐linear Coherent and Time‐resolved Raman Spectroscopymentioning

confidence: 99%

“…Precision errors because of experimental and fitting effects were discussed. [93] Dennis et al carried out high dynamic-range thermometry at 5 kHz in hydrogen-air diffusion flame using chirped-probe-pulse femtosecond CARS scattering. Measurements were performed at different heights and radial locations within the jet diffusion flame, up to 16 nozzle exit diameters downstream, and the temperature precision of the system was found to be better than 2.0% at 2,200 K. [94] Kano and coworkers reviewed the field of hyperspectral coherent Raman imaging with emphasis on basic principles, theory, instrumentation, and applications to the life sciences.…”

Section: Coherent Anti-stokes Raman Spectroscopy (Cars)mentioning

confidence: 99%

Recent advances in linear and non‐linear Raman spectroscopy. Part XI

Nafie

2017

J Raman Spectroscopy

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This review, published annually, provides an overview of advances in the field of Raman spectroscopy as found in papers published in the preceding calendar year in the Journal of Raman Spectroscopy (JRS), as well as in trends over the past decade across journals that have published papers important to the field of Raman spectroscopy. This information is obtained from statistical data on article counts obtained from Clarivate Analytics' Web of Science Core Collection by year and by subfield of Raman spectroscopy. Additional information is gleaned from presentations at the IX International Conference on Advanced Vibrational Spectroscopy (ICAVS‐9) in Victoria, British Columbia, Canada, in June 2017 and those featuring Raman scattering at SCIX 2017 organized by the Federation of Analytical Chemistry and Spectroscopy Societies (FACSS) in Reno, Nevada, USA, in October 2017. Coverage is also provided for topics from the European Conference on Non‐linear Optical Spectroscopy (ECONOS 2017) held in April 2017 in Jena, Germany, and the Ninth Congress on the Application of Raman in Art and Archaeology (RAA 2017) in October 2017 in Evora, Portugal. Finally, papers published in JRS in 2016 are highlighted and arranged by topics at the frontier of Raman spectroscopy. Based on this survey information, it is clear that Raman spectroscopy maintains a rapidly expanding influence across a wide range of novel disciplines and applications that provide sensitive photonic information of matter at the molecular level.

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“…Good agreement between measured O 2 concentration and theory was shown in their calibration measurements on a Hencken burner. Carbon dioxide concentrations and temperatures have also been probed in counterflow diffusion flames [27] , CO 2 seeded H 2 diffusion flames [28] , exhaust streams of a liquid-fueled combustor [29] , flat flames [30,31] , and in a gas cell [30] . Both higher and lower measured CO 2 concentrations than those from calculations were observed.…”

Section: Introductionmentioning

confidence: 99%

Dual-pump vibrational CARS measurements of temperature and species concentrations in turbulent premixed flames with CO2 addition

Han

Satija

Kim

et al. 2017

Combustion and Flame

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a b s t r a c tA dual-pump vibrational coherent anti-Stokes Raman scattering (DPVCARS) system was applied for simultaneous temperature and species concentration measurements in jet flames on a newly developed piloted axisymmetric reactor assisted turbulent (PARAT) premixed flame burner. Turbulent lean premixed methane/air round jet flames with varying CO 2 dilution were stabilized using an annular flow of hydrogen at the flame base. Carbon dioxide was injected into the fuel stream to simulate effects of dry exhaust gas recirculation (EGR). The flames were operated at a nearly constant Reynolds number, Lewis number, and adiabatic flame temperature to minimize thermal and transport effects. Velocity boundary conditions at the burner exit were measured using particle image velocimetry. Simultaneous temperature and major species concentrations (O 2 and CO 2 ) were measured along the axial direction at the burner centerline and along the radial direction at representative axial locations above the burner. Progress variables calculated based on the temperatures were used to study the mean flame brush thickness and the turbulent burning velocity. Probability density functions (PDFs) of temperature at various locations are presented and discussed. The DPVCARS measurements provide an experimental database including temperature and turbulent burning velocity for combustion model evaluation and validation and demonstrated a strong potential for flame structure investigation with future improvement on spatial resolution and signal to noise ratio. The merits and limitations of vibrational CARS for diagnostics in turbulent premixed combustion are discussed. The results show that flames with CO 2 addition depart from the universal mean flame brush structure, while their RMS fluctuation values at an identical mean temperature collapse with the undiluted flame. The CO 2 addition increases the combustion intensity with a decrease in turbulent burning velocity when minimizing the thermal and transport effects.

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WIDECARS spectra fitting in a premixed ethylene–air flame

Cited by 13 publications

References 17 publications

Adaptive modeling powers fast multiparameter fitting of CARS spectra

Adaptive modeling powers fast multiparameter fitting of CARS spectra

Recent advances in linear and non‐linear Raman spectroscopy. Part XI

Dual-pump vibrational CARS measurements of temperature and species concentrations in turbulent premixed flames with CO2 addition

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