Absolute Temperature Fields in Flames by 2D‐LIF of OH Using Excimer Lasers and CARS Spectroscopy

Arnold, A.; Lange, Birgit; Bouché, T.; Heitzmann, T.; Schiff, G.; Ketterle, Wolfgang; Monkhouse, P.; Wolfram, Joy

doi:10.1002/bbpc.19920961009

Cited by 53 publications

(14 citation statements)

References 38 publications

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“…This is especially important if information from more than one image has to be combined, e.g. for temperature measurements with the two-line method [ 5 ] . Furthermore, technical applications of approved methods for laboratory scale research require modifications not only for the measurement equipment, but usually also for the combustor.…”

Section: General Features Of Multi-dimensional Light Sheet Techniquesmentioning

confidence: 99%

“…17, that distortions caused for example by absorption due to oil on the windows cancel in the temperature field. To account for different detection efficiencies and different fluorescence quantum yields of the two levels it is appropriate to calibrate the system with a measurement under conditions with known temperature [5]. The calibration to absolute temperature values was performed by using a calculated …”

Section: Diesel Enginesmentioning

confidence: 99%

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2D‐Diagnostics in Industrial Devices

Arnold

Bräumer

Buschmann

et al. 1993

Ber Bunsenges Phys Chem

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The high spectral brightness of tunable high power excimer lasers allows the two‐ and three‐dimensional application of techniques like laser‐induced fluorescence (LIF), Mie and Rayleigh scattering for industrial applications. The construction of these lasers allows easy transportation and installation to perform measurements at combustion facilities which can not be moved. In combination with suitable filters and gated image‐intensified CCD cameras techniques are now available to measure multi‐dimensional distributions of temperatures and concentrations. Simultaneous measurements of temperature fields and hydroxyl radical distributions were performed to study the influence of turbulence on large premixed natural gas flames. A combination of temperature and nitric oxide concentration measurements yielded information about the correlations between NO formation and burner design in domestic gas burners. LIF and Mie scattering of fuel and hydroxyl radicals were used for measurements in IC engine simulators, Otto and Diesel engines.

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Section: General Features Of Multi-dimensional Light Sheet Techniquesmentioning

confidence: 99%

Section: Diesel Enginesmentioning

confidence: 99%

2D‐Diagnostics in Industrial Devices

Arnold

Bräumer

Buschmann

et al. 1993

Ber Bunsenges Phys Chem

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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%

“…However, for the scheme of Ref. [38], the relatively small energy spacing of the respective ground state levels may also be a problem, as will be discussed below.…”

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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“…In contrast to conventional two-color temperature imaging techniques (e.g., [11]), the multi-line approach has the advantage of being calibrationfree and robust against background signal as long as the shape of the excitation spectra can still be distinguished on top of the background signal and the background does not strongly vary with excitation wavelength within the investigated spectral range. Therefore, especially in highpressure flames, NO-LIF transitions must be chosen that do not interfere with LIF from hot O 2 [12].…”

mentioning

confidence: 97%

Effect of fluctuations on time-averaged multi-line NO-LIF thermometry measurements of the gas-phase temperature

et al. 2015

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chemistry and therefore, e.g., combustion efficiency and pollutant formation. Multi-line nitric oxide (NO)-laserinduced fluorescence (LIF) thermometry imaging enables accurate measurements of gas-phase temperature distributions in a spatial plane without the necessity of calibration [1]. The technique relies on the temperature dependence of NO LIF excitation spectra [1][2][3]. In thermal equilibrium, the temperature dependence of the population of the rotational ground state energy levels is described by the Boltzmann distribution. A laser is tuned across the vibronic transitions of the electronic A-X absorption band and the population fractions of individual rotational quantum states are probed by recording the respective LIF signal intensity with an intensified CCD camera. Excitation spectra are then extracted for each pixel from the stack of images taken for each laser wavelength position. Simulated spectra are then fitted to the experimental spectra with absolute temperature as the adjustable parameter. Spectral line broadening and background signals (e.g., scattered laser light or broad-band fluorescence) are included in the fitting routine.Multi-line techniques have demonstrated their robustness in stable low-pressure [4,5], atmospheric pressure [6], and high-pressure flames [7,8] as well as in systems with a large scattering background such as sooting flames [1] and spray systems [9,10]. In contrast to conventional two-color temperature imaging techniques (e.g., [11]), the multi-line approach has the advantage of being calibrationfree and robust against background signal as long as the shape of the excitation spectra can still be distinguished on top of the background signal and the background does not strongly vary with excitation wavelength within the investigated spectral range. Therefore, especially in highpressure flames, NO-LIF transitions must be chosen that do not interfere with LIF from hot O 2 [12]. The method, however, lacks single-shot capability because the spectra Abstract Multi-line NO laser-induced fluorescence (LIF) thermometry enables accurate gas-phase temperature imaging in combustion systems through least-squares fitting of excitation spectra. The required excitation wavelength scan takes several minutes which systematic biases the results in case of temperature fluctuations. In this work, the effect of various types (linear, Gaussian and bimodal) and amplitudes of temperature fluctuations is quantified based on simulated NO-LIF excitation spectra. Temperature fluctuations of less than ±5 % result in a negligible error of less than ±1 % in temperature for all cases. Bimodal temperature distributions have the largest effect on the determined temperature. Symmetric temperature fluctuations around 900 K have a negligible effect. At lower mean temperatures, fluctuations cause a positive bias leading to over-predicted mean temperatures, while at higher temperatures the bias is negative. The results of the theoretical analysis were applied as a guide for interpreting experimental multi-line ...

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Absolute Temperature Fields in Flames by 2D‐LIF of OH Using Excimer Lasers and CARS Spectroscopy

Cited by 53 publications

References 38 publications

2D‐Diagnostics in Industrial Devices

2D‐Diagnostics in Industrial Devices

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

Effect of fluctuations on time-averaged multi-line NO-LIF thermometry measurements of the gas-phase temperature

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