Extension of the Gladstone-Dale equation for flame flow field diagnosis by optical computerized tomography

Chen, Yunyun; Li, Zhenhua; Song, Yang; He, Anzhi

doi:10.1364/ao.48.002485

Cited by 19 publications

(6 citation statements)

References 15 publications

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“…The sufficiency of such a partial structure for determining the refractive index of a mixture was verified using experimental data [16]. It should be noted that when working with a hydrogen-oxygen flame, taking into account ionization can affect the accuracy of determining the temperature [17].…”

Section: Reconstruction Of the Radial Temperature Profile In The Structure Of A Hydrogen-air Diffusion Flamementioning

confidence: 91%

Method of Polychromatic Hilbert Diagnostics of Phase and Temperature Perturbations of Axisymmetric Flames

Арбузов

Arbuzov

Zolotukhina

et al. 2021

Proceedings of the 31th International Conference on Computer Graphics and Vision. Volume 2

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The work is aimed at solving the scientific and practical problem of non-disturbing diagnostics of the phase and temperature fields of reacting jets and flames. On the example of an axisymmetric hydrogen-diffusion flame and a hot air flow from a candle flame, a method was developed that is adequate to the problem being solved, based on Hilbert polychromatic visualization of phase optical density fields, measuring the temperature profile in selected areas of the medium under study, pixel-by-pixel processing of RAW images recorded by a photographic matrix in RGB channels. The visualized Hilbert structures carry information about the phase optical density perturbations induced by the temperature field. The phase structure of the probing light field in the axial symmetry approximation of the flame under investigation is analyzed using the Abel transform. Iterative selection of radial temperature profiles, adapted Bezier curves, is performed with the subsequent calculation of the spatial structure of the refractive index and phase function. The reconstruction of the temperature field by the example of the study of a hydrogen-air flame is carried out taking into account the diversity of the partial optical properties of the gas mixture in a model consistent with the Gladstone-Dale dispersion formula. The influence of disturbances in the air surrounding the flame on its axial symmetry is discussed. The criterion for the reliability of the research results is a comparison of the hilbertograms obtained in the experiment and the hilbertograms reconstructed from phase structures induced by temperature fields.

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Section: Reconstruction Of the Radial Temperature Profile In The Structure Of A Hydrogen-air Diffusion Flamementioning

confidence: 91%

Method of Polychromatic Hilbert Diagnostics of Phase and Temperature Perturbations of Axisymmetric Flames

Арбузов

Arbuzov

Zolotukhina

et al. 2021

Proceedings of the 31th International Conference on Computer Graphics and Vision. Volume 2

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show abstract

“…On the other hand, this argumentation can be supported by the Gladstone-Dale (G-D) equation, which makes the connection between material density (ρ) and its RI (n) following: n ¼ 1 þ kρ, where k is the G-D constant. 38 The overall changes in RI over a continuous spectral NIR region highlight the pathophysiologic changes occurring in the brain in response to thermal insult and demonstrate our ability to resolve an additional intrinsic optical parameter.…”

Section: °C 43°cmentioning

confidence: 93%

Spectral refractive index assessment of turbid samples by combining spatial frequency near-infrared spectroscopy with Kramers–Kronig analysis

2018

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A practical algorithm for estimating the wavelength-dependent refractive index (RI) of a turbid sample in the spatial frequency domain with the aid of Kramers-Kronig (KK) relations is presented. In it, phase-shifted sinusoidal patterns (structured illumination) are serially projected at a high spatial frequency onto the sample surface (mouse scalp) at different near-infrared wavelengths while a camera mounted normally to the sample surface captures the reflected diffuse light. In the offline analysis pipeline, recorded images at each wavelength are converted to spatial absorption maps by logarithmic function, and once the absorption coefficient information is obtained, the imaginary part (k) of the complex RI (CRI), based on Maxell's equations, can be calculated. Using the data represented by k, the real part of the CRI (n) is then resolved by KK analysis. The wavelength dependence of n ( λ ) is then fitted separately using four standard dispersion models: Cornu, Cauchy, Conrady, and Sellmeier. In addition, three-dimensional surface-profile distribution of n is provided based on phase profilometry principles and a phase-unwrapping-based phase-derivative-variance algorithm. Experimental results demonstrate the capability of the proposed idea for sample's determination of a biological sample's RI value.

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“…Opensource CFD solver laminarSMOKE is used to provide the density distribution about the central plane of CDF (Cuoci et al, 2013a;Cuoci et al, 2013b;Cuoci et al, 2015), and three-dimensional interpolation is performed to obtain the density distribution of the whole cylindrical region. Subsequently, the refractive index distribution can be calculated with the Gladstone-Dale formula (Chen et al, 2009) and was then imported for the tracing simulation. The simulations were carried out in the case of the existence and nonexistence of the CDF modeling, respectively.…”

Section: Feasibility Analysismentioning

confidence: 99%

Planar Light Extinction Measurement of Soot Volume Fraction in Laminar Counterflow Diffusion Flames

Zhou

et al. 2021

Front. Mech. Eng.

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A cost-effective and straightforward light extinction method has been extensively used for measurement of soot volume fraction (SVF) in sooting flames. The traditional pointwise measurement with translation stage suffers from relatively time-consuming operation and low spatial resolution. In the current study, the planar light extinction method is processed by utilizing a CMOS camera to image the combustion field of counterflow diffusion flame (CDF) backlit with the lamp. Collimated and diffuse optical layouts were adopted to explore the feasibility. Investigations of beam-steering effects are presented and discussed through a combination of computational fluid dynamics (CFD) and ray tracing simulations. Measured SVF are compared to the well-validated laser-induced incandescence (LII) measurements. Current measurements show that the diffuse optical layout is feasible and robust to provide accurate and more efficient measurement of the SVF in CDF with superior spatial resolution (21.65 μm).

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Extension of the Gladstone-Dale equation for flame flow field diagnosis by optical computerized tomography

Cited by 19 publications

References 15 publications

Method of Polychromatic Hilbert Diagnostics of Phase and Temperature Perturbations of Axisymmetric Flames

Method of Polychromatic Hilbert Diagnostics of Phase and Temperature Perturbations of Axisymmetric Flames

Spectral refractive index assessment of turbid samples by combining spatial frequency near-infrared spectroscopy with Kramers–Kronig analysis

Planar Light Extinction Measurement of Soot Volume Fraction in Laminar Counterflow Diffusion Flames

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