A combustion temperature and species standard for the calibration of laser diagnostic techniques

Sutton, Gavin; Levick, A. P.; Edwards, G. J.; Greenhalgh, Douglas A.

doi:10.1016/j.combustflame.2006.07.013

Cited by 57 publications

(27 citation statements)

References 6 publications

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“…Rayleigh scattering involves the elastic scattering of light from atoms and molecules that undergo an oscillating polarization at the incident laser frequency, causing them to scatter light at the same wavelength. This technique has been shown to provide temperature accuracies of <1% [2]. However, this level of accuracy requires determination of not only the dependence of scattering cross section on temperature for each molecule that is present within the measurement volume, but also the concentration of each molecule.…”

Section: Introductionmentioning

confidence: 99%

Comparison of line-peak and line-scanning excitation in two-color laser-induced-fluorescence thermometry of OH

Kostka¹,

Roy²,

Lakusta³

et al. 2009

Appl. Opt.

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Two-line laser-induced-fluorescence (LIF) thermometry is commonly employed to generate instantaneous planar maps of temperature in unsteady flames. The use of line scanning to extract the ratio of integrated intensities is less common because it precludes instantaneous measurements. Recent advances in the energy output of high-speed, ultraviolet, optical parameter oscillators have made possible the rapid scanning of molecular rovibrational transitions and, hence, the potential to extract information on gas-phase temperatures. In the current study, two-line OH LIF thermometry is performed in a wellcalibrated reacting flow for the purpose of comparing the relative accuracy of various line-pair selections from the literature and quantifying the differences between peak-intensity and spectrally integrated line ratios. Investigated are the effects of collisional quenching, laser absorption, and the integration width for partial scanning of closely spaced lines on the measured temperatures. Data from excitation scans are compared with theoretical line shapes, and experimentally derived temperatures are compared with numerical predictions that were previously validated using coherent anti-Stokes-Raman scattering. Ratios of four pairs of transitions in the A 2 Σ+←X 2 Π (1,0) band of OH are collected in an atmospheric-pressure, near-adiabatic hydrogen-air flame over a wide range of equivalence ratios-from 0.4 to 1.4. It is observed that measured temperatures based on the ratio of Q 1( 14)/Q 1( 5) transition lines result in the best accuracy and that line scanning improves the measurement accuracy by as much as threefold at lowequivalence-ratio, low-temperature conditions. These results provide a comprehensive analysis of the procedures required to ensure accurate two-line LIF measurements in reacting flows over a wide range of conditions. Keywords coherent scattering, fluid structure interaction, fluorescene, gas absorption, laser produced plasmas, microlenses, scanning, temperature sensors, coherent anti-Stokes, collisional quenching, comprehensive analysis, energy output, equivalence ratios, gasphase, laser absorption, laser induced fluorescence, LIF thermometry, low temperatures, measurement accuracy, numerical predictions RightsThis paper was published in Applied Optics and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: https://www.osapublishing.org/ ao/abstract.cfm?uri=ao-48-32-6332. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law. Two-line laser-induced-fluorescence (LIF) thermometry is commonly employed to generate instantaneous planar maps of temperature in unsteady flames. The use of line scanning to extract the ratio of integrated intensities is less common because it precludes instantaneous measurements. Recent advances in the energy output of high-speed, ultraviolet, optical parameter oscillators have made p...

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Section: Introductionmentioning

confidence: 99%

Comparison of line-peak and line-scanning excitation in two-color laser-induced-fluorescence thermometry of OH

Kostka¹,

Roy²,

Lakusta³

et al. 2009

Appl. Opt.

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“…Further, Fuest et al [16] discussed the temperature dependence of the species cross section and found them to vary by less than 1% in his DME flame, whereas a variation of up to 2% towards low temperatures was found in [54]. By employing the relationships suggested in [54] we estimate that the cross section inaccuracy with increasing temperature is not more than 2%. R1, R3 R1, R3 In the laminar case, the species and temperature are fully available and the evaluation of the Rayleigh ratio can thus be performed based on this detailed simulation without any further assumption at each location in the flow field.…”

Section: Numerical Evaluation Of the Rayleigh Signalmentioning

confidence: 82%

A Combined Experimental and Numerical Study of Laminar and Turbulent Non-piloted Oxy-fuel Jet Flames Using a Direct Comparison of the Rayleigh Signal

Hunger

Zulkifli

Williams

et al. 2015

Flow Turbulence Combust

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“…To perform such a calculation, a McKenna premixed flat-flame burner was used to generate the experimental flame because it has a controlled and quantifiable local velocity and a wellcharacterized temperature distribution [22,23]. The RTC assembly was mounted over the 60 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 mm-diameter burner head, which is composed of sintered stainless steel and is water-cooled.…”

Section: Methodsmentioning

confidence: 99%

An Approach to Thermocouple Measurements That Reduces Uncertainties in High-Temperature Environments

Krishnan

Kumfer

et al. 2015

Energy Fuels

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Obtaining accurate temperature measurements with thermocouples in flame environments is challenging due to the effects of radiative heat losses, as these losses are difficult to quantify. Efforts to minimize radiative losses by, for example, suction pyrometry, often result in a significant sacrifice in spatial resolution. In this work, a new experimental methodology is presented that both minimizes the temperature correction and allows the remaining correction to be accurately quantified. The approach is based on increasing and controlling the convective heat transfer to the thermocouple junction, and is accomplished by spinning the thermocouple at high speed. The rotation yields a large and known convective velocity over the thermocouple. Heat transfer can then be modeled for the thermocouple, and a functional relationship between temperature and rotational speed can be found. Fitting this model to the data allows for an accurate temperature correction. To test the feasibility of the rotating thermocouple (RTC) technique for temperature measurement in high temperature gases, experiments were conducted over a range of rotational speeds in a controlled flame where the temperature was known. The measured thermocouple temperatures as a function of rotational speed closely match the theoretical temperatures, yielding a straightforward approach to highly accurate gas temperature measurement. The results also demonstrate limited perturbation to the flow field, even at high rotational speeds. Finally, a method of deconvolution is described that significantly enhances the spatial resolution of the technique, approaching that of a stationary thermocouple. Area (m 2 ) D Diameter of bead (m) ℎ Convective heat transfer coefficient (W/m 2 -K) RTC Rotating thermocouple L Length (m) ܳ ሶ Heat flux (W) r Radius (m) T Temperature (°C) V Velocity (m/s) ω Rotational speed (revolutions/min)

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A combustion temperature and species standard for the calibration of laser diagnostic techniques

Cited by 57 publications

References 6 publications

Comparison of line-peak and line-scanning excitation in two-color laser-induced-fluorescence thermometry of OH

Comparison of line-peak and line-scanning excitation in two-color laser-induced-fluorescence thermometry of OH

A Combined Experimental and Numerical Study of Laminar and Turbulent Non-piloted Oxy-fuel Jet Flames Using a Direct Comparison of the Rayleigh Signal

An Approach to Thermocouple Measurements That Reduces Uncertainties in High-Temperature Environments

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