Tomographic Imaging of Flames: Assessment of Reconstruction Error Based on Simulated Results

Guha, Avishek; Schoegl, Ingmar

doi:10.2514/1.b34831

Cited by 22 publications

(5 citation statements)

References 43 publications

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“…However, the fractional fitting residuals were typically less than 3% for CO, less than 2% for CO 2 , and less than 3% for H 2 O, supporting the appropriateness of the Voigt line fitting routine as an approximation. Spectral absorbance measurements can then be obtained at discrete locations from the axis of symmetry and, using Abel's integral equation [33,34], can be related to the radial distribution of the integrated spectral absorption coefficient, K(r) (cm −2 ). This relationship is described by equation ( 6):…”

Section: Laser Absorption Spectroscopymentioning

confidence: 99%

Localized characteristic velocity (c*) for rocket combustion analysis based on gas temperature and composition via laser absorption spectroscopy

Bendana

Sanders

Stacy

et al. 2021

Meas. Sci. Technol.

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In this work, a method for experimentally determining a local characteristic velocity, , is presented for purposes of analyzing rocket combustion progress based on in-situ laser absorption spectroscopy measurements of temperature and gas composition. Measuring from spatially-varying thermochemical properties provides an alternative to the classical evaluation, which uses global chamber pressure and mass flow rate measurements. Accordingly, the novel method provides more detailed insight to the underlying mechanisms (multi-phase thermochemistry, diffusive mixing, turbulence, etc) governing combustion performance in the spatial domain. The method is demonstrated on an RP-2/O2 liquid-propellant rocket engine (LRE) and a PMMA/O2 hybrid rocket combustion experiment. Localized results for the LRE are obtained via in-chamber measurements of temperature, CO, and CO2 and are presented over a range of pressures ( 28–83 bar) and mixture ratios (MR = 2.5–5). For the hybrid rocket combustion experiment, one-dimensional tomographic reconstruction techniques are used to spatially-resolve the flow-field thermochemistry and obtain spatially-resolved measurements of temperature, CO, CO2, and H2O. These measurements are compiled to obtain spatially-resolved images of the combustion zone. The results from both experiments are compared to the theoretical expected from chemical equilibrium, providing for a method to assess combustion performance or progress locally within the combustion zone.

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Section: Laser Absorption Spectroscopymentioning

confidence: 99%

Localized characteristic velocity (c*) for rocket combustion analysis based on gas temperature and composition via laser absorption spectroscopy

Bendana

Sanders

Stacy

et al. 2021

Meas. Sci. Technol.

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“…Simulations combining WMS with CT have proved the superiority of WMS-TDLAT technology. 19,20 However, the kf/1f-WMS harmonic signals are nonlinear and line-of-sight (LOS) measurements do not represent the integrals of any physical quantity, which limits the combined application of WMS with the classical CT method. 21 In recent research, a new branch of the WMS method was proposed-natural logarithm wavelength modulation spectroscopy (ln-WMS).…”

Section: Introductionmentioning

confidence: 99%

“…The distortion of the harmonic signal by the coupling of non‐uniformity and laser characteristic also causes systematic errors that are difficult to evaluate in the measurement results. Simulations combining WMS with CT have proved the superiority of WMS‐TDLAT technology 19,20 . However, the kf /1 f ‐WMS harmonic signals are nonlinear and line‐of‐sight (LOS) measurements do not represent the integrals of any physical quantity, which limits the combined application of WMS with the classical CT method 21 .…”

Section: Introductionmentioning

confidence: 99%

Linear calibration‐free wavelength modulation spectroscopy

Lin

et al. 2021

Micro & Optical Tech Letters

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This article presents a new linear calibration-free wavelength modulation spectroscopy (LCF-WMS) technique for gas sensing. By combining the natural logarithms of the transmitted intensity and background signals, this technique eliminates the effects of the intensity, intensity modulation, and the modulation phase to obtain integrable harmonic signals along the line-of-sight and thus realize calibration-free measurements. To illustrate the validity of the LCF-WMS technique, it was applied to measurement of the water vapor concentration in air at ambient temperature. Because of its specific features of line-of-sight integrability and baseline independence, this method will be advantageous in absorption tomography and high-pressure applications.

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“…Tunable diode laser based absorption spectroscopy emerged as an attractive solution to monitor temperature and species concentration in such applications, due to its capability of providing path length average information across the 20 m wide furnace, with no physical probe exposed to the flue gas [2]. Recent developments in using multiple beams and hyperspectral topographic techniques could even evaluate the non-uniformity of the temperature field, which has huge potential impact on the design and operation of industrial furnaces [3,4]. This paper reports our preliminary effort in bring the TDLAS technique from the lab to the large scale industrial furnaces, and a prototype compact TDL sensor for temperature for SMR flue gas temperature monitoring purposes, which later on could develop into multi-species/multi-path measurement.…”

mentioning

confidence: 99%

A tunable diode laser sensor for temperature measurement in large-scale hydrogen generation furnaces

Zhao

Guha

2014

Light, Energy and the Environment

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Tomographic Imaging of Flames: Assessment of Reconstruction Error Based on Simulated Results

Cited by 22 publications

References 43 publications

Localized characteristic velocity (c*) for rocket combustion analysis based on gas temperature and composition via laser absorption spectroscopy

Localized characteristic velocity (c*) for rocket combustion analysis based on gas temperature and composition via laser absorption spectroscopy

Linear calibration‐free wavelength modulation spectroscopy

A tunable diode laser sensor for temperature measurement in large-scale hydrogen generation furnaces

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