Special Issue "Tomographic and Volumetric Diagnostics in Flames"

A special issue of Energies (ISSN 1996-1073).

Deadline for manuscript submissions: 31 March 2020.

Special Issue Editors

Prof. Dr. Khadijeh Mohri
E-Mail Website
Guest Editor
Institute for Combustion and Gas Dynamics (IVG), Fluid Dynamics, University of Duisburg-Essen, 47047 Duisburg, Germany
Interests: Tomographic techniques in energy- and process-technology; Flame tomography; Evolutionary reconstruction techniques (ERT); Background-oriented schlieren tomography; Multi-simultaneous measurements
Prof. Dr.-Ing. Andreas M. Kempf
E-Mail Website
Guest Editor
Institute for Combustion and Gas Dynamics (IVG), Fluid Dynamics, University of Duisburg-Essen, 47047 Duisburg, Germany
Interests: Flame tomography; Large-eddy simulation of combustion; Direct numerical simulation of flames; Nano-particle synthesis; Modelling

Special Issue Information

Dear Colleagues,

Stringent regulations concerning pollutant and greenhouse gas emissions, safety and cost concerns, and fuel load and stability issues all call for the need to improve combustion devices. This can only be achieved with an in-depth understanding of realistic flames, which, in most cases, are turbulent. A fundamental understanding of such flames, as well as advanced numerical simulations, require experimental data that should ideally be time-resolved and volumetric, due to the inherent unsteadiness and three-dimensionality of the flames.

With this Special Issue, we aim to present recent work on tomographic and volumetric imaging in flames. We advise that papers should not exceed 12 pages in length. Review papers are also welcome, but please contact us if you plan to prepare one.

Prof. Dr. Khadijeh Mohri
Prof. Dr.-Ing. Andreas M. Kempf
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Flame tomography
  • Extracting quantitative information from flame reconstructions
  • Phantom study strategies for tomography algorithm development
  • Novel tomography algorithms
  • High accuracy camera calibration methods
  • Laser-based techniques
  • Light field imaging
  • Time-resolved data
  • High resolution data
  • Industrial applications
  • Thermo-acoustics applications
  • Methods for the analysis of volumetric data

Published Papers (2 papers)

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Research

Open AccessFeature PaperArticle
Axisymmetric Linear Hyperspectral Absorption Spectroscopy and Residuum-Based Parameter Selection on a Counter Flow Burner
Energies 2019, 12(14), 2786; https://doi.org/10.3390/en12142786 - 19 Jul 2019
Abstract
Chemical species tomography enables non-invasive measurements of temperatures and concentrations in gas phase processes. In this work, we demonstrate the recently introduced linear hyperspectral absorption tomography (LHAT) on an axisymmetric counterflow burner used for speciation studies of Oxyfuel combustion. As LHAT reconstructs spectrally [...] Read more.
Chemical species tomography enables non-invasive measurements of temperatures and concentrations in gas phase processes. In this work, we demonstrate the recently introduced linear hyperspectral absorption tomography (LHAT) on an axisymmetric counterflow burner used for speciation studies of Oxyfuel combustion. As LHAT reconstructs spectrally resolved local absorption coefficient spectra, the physical plausibility of these reconstructed spectra degrades with an over-regularization of the tomographic problem. As presented in this work, this behavior can be employed in a novel regularization parameter choice method based on the residuals of local spectroscopic fits to the reconstructed spectra. After determining the regularization parameter, the reconstructions of the temperature and water mole fraction profiles of different flames are compared to numerical simulations, showing a good agreement. Full article
(This article belongs to the Special Issue Tomographic and Volumetric Diagnostics in Flames)
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Graphical abstract

Open AccessArticle
3D Evolutionary Reconstruction of Scalar Fields in the Gas-Phase
Energies 2019, 12(11), 2075; https://doi.org/10.3390/en12112075 - 30 May 2019
Cited by 1
Abstract
An evolutionary reconstruction technique (ERT) was developed for three-dimensional (3D) reconstruction of luminescent objects, in particular turbulent flames for the first time. The computed tomography (CT) algorithm is comprised of a genetic algorithm (GA) and a ray-tracing software. To guide the reconstruction process, [...] Read more.
An evolutionary reconstruction technique (ERT) was developed for three-dimensional (3D) reconstruction of luminescent objects, in particular turbulent flames for the first time. The computed tomography (CT) algorithm is comprised of a genetic algorithm (GA) and a ray-tracing software. To guide the reconstruction process, a mask is introduced. It uses a Metropolis algorithm (MA) to sample locations where specific genetic operators can be applied. Based on an extensive parameter study, performed on several types of phantoms, the ability of our algorithm for 3D reconstructions of fields with varying complexities is demonstrated. Furthermore, it was applied to three experiments, to reconstruct the instantaneous chemiluminescence field of a bunsen flame, a highly turbulent swirl flame and the turbulent Cambridge-Sandia stratified flame. Additionally, we show direct and quantitative comparison to an advanced computed tomography of chemiluminescence (CTC) method that is based on an algebraic reconstruction technique (ART). The results showed good agreement between CTC and ERT using both phantom data from flame simulations, and experimental data. Full article
(This article belongs to the Special Issue Tomographic and Volumetric Diagnostics in Flames)
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Figure 1

Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Type: Article
Title: Image Reconstruction for Chemical Species Tomography Using Full Spectral Data
Authors: N. Polydorides 1, M. Lengden 2, C. Liu 1, G. Humphries 2, S.-A. Tsekenis 1, D. Wilson 2 and H. McCann 1,*
Affiliations
1   School of Engineering, Institute for Digital Communications, University of Edinburgh, Edinburgh, UK; [email protected] (N.P.); [email protected] (C.L.); [email protected] (S.-A.T.);
2   Department of Electrical and Electronic Engineering, University of Strathclyde, Glasgow, UK; [email protected] (M.L.); [email protected] (G.H.); [email protected] (D.W.);
* Correspondence: [email protected] 
Abstract: We consider the linear inverse problem of Chemical Species Tomography using spectral absorption data, such as those acquired in wavelength modulation spectroscopy. We introduce a novel approach that exploits the rich spectral information to overcome some of the limitations of CST. Under isobaric measurement conditions and known species temperature, our approach results in a linear well-posed estimation problem. The concentration images thus obtained have enhanced noise robustness, and spatial resolution significantly better than previous inversion methods for the same number of optical paths. We demonstrate the approach by CST of carbon dioxide in combustion exhaust, through both simulation and experimental measurement.
Keywords: Carbon dioxide concentration, chemical species tomography, linear attenuation, inverse problem, image reconstruction, Near-IR absorption, spectroscopy

Type: Article
Title: Two-dimensional tomographic simultaneous multi-species visualization in laminar and turbulent flames
Authors: Thomas Häber 1,*, Rainer Suntz 1 and Henning Bockhorn 2
Affiliations:
1 Institute of Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology (KIT); [email protected], [email protected]
2 Engler-Bunte-Institute, Chair of Combustion Technology, Karlsruhe Institute of Technology (KIT); [email protected]
* Correspondence: [email protected]
Abstract: In recent years, the tomographic visualization of laminar and turbulent flames has received much attention. In most cases, either the integral flame luminescence or the chemiluminescence of a single species is detected and used for the tomographic reconstruction. In this work, we present a novel 2D emission tomographic setup that allows for the simultaneous detection of multiple species (e.g. OH*, CH* and soot but not limited to these) using a single image intensified CCD camera. We demonstrate the simultaneous detection of OH* (310nm), CH* (430nm) and soot (750nm) in laminar methane/air, as well as turbulent methane/air and ethylene/air diffusion flames. Taking advantage of the strong spatial (and temporal) coupling of OH* and CH* in laminar and moderate turbulent flames, multi-species tomography enables us to quantify the reconstruction quality independent of any phantom studies. This is especially import in turbulent flames, where it is difficult to separate measurement noise from turbulent fluctuations. We will show that reconstruction methods based on Tikhonov regularization should be preferred over the widely used algebraic reconstruction technique (ART) and multiplicative algebraic reconstruction techniques (MART), especially for high-speed imaging or generally in the limit of low signal-to-noise ratio. We will also investigate the possibilities and limitations of the tomographic approach to distinguish between locally premixed, partially-premixed and non-premixed conditions, based on evaluating the local intensity ratio of OH* and CH*.
Keywords: optical emission tomography, combustion, chemiluminescence, Tikhonov regularization, algebraic reconstruction technique, laminar diffusion flame, turbulent diffusion flame, local equivalence ratio

Type: Article
Title: Two-Dimensional Tomographic Simultaneous Multi-Species Visualization in Laminar and Turbulent Flames
Authors: Thomas Häber 1,*, Rainer Suntz 1 and Henning Bockhorn 2
Affiliations:
1
Institute of Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology (KIT); [email protected], [email protected]
2 Engler-Bunte-Institute, Chair of Combustion Technology, Karlsruhe Institute of Technology (KIT); [email protected]
* Correspondence: [email protected]
Abstract: In recent years, the tomographic visualization of laminar and turbulent flames has received much attention. In most cases, either the integral flame luminescence or the chemiluminescence of a single species is detected and used for the tomographic reconstruction. In this work, we present a novel 2D emission tomographic setup that allows for the simultaneous detection of multiple species (e.g. OH*, CH* and soot but not limited to these) using a single image intensified CCD camera. We demonstrate the simultaneous detection of OH* (310nm), CH* (430nm) and soot (750nm) in laminar methane/air, as well as turbulent methane/air and ethylene/air diffusion flames. Taking advantage of the strong spatial (and temporal) coupling of OH* and CH* in laminar and moderate turbulent flames, multi-species tomography enables us to quantify the reconstruction quality independent of any phantom studies. This is especially import in turbulent flames, where it is difficult to separate measurement noise from turbulent fluctuations. We will show that reconstruction methods based on Tikhonov regularization should be preferred over the widely used algebraic reconstruction technique (ART) and multiplicative algebraic reconstruction techniques (MART), especially for high-speed imaging or generally in the limit of low signal-to-noise ratio. We will also investigate the possibilities and limitations of the tomographic approach to distinguish between locally premixed, partially-premixed and non-premixed conditions, based on evaluating the local intensity ratio of OH* and CH*.
Keywords: optical emission tomography, combustion, chemiluminescence, Tikhonov regularization, algebraic reconstruction technique, laminar diffusion flame, turbulent diffusion flame, local equivalence ratio

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