Mohri Group - Tomography

Welcome to the tomography group!

The focus of work is the development and application of tomographic techniques in energy- and process-technology, for three-dimensional (3D) reconstruction of different modalities. Computed Tomgoraphy (CT) is a mathematical tool that is used for reconstructing a field in 3D, based on projections measurements that are obtained from different angles around the field. The projections, which contain some information about a property within the field could be in the form of emission or transmission data for example. We explore different types of algorithms including the Algebraic Reconstruction Technique (ART), Evolutionary Genetic Algorithm (GA) and Baysian algorithms.
So far we have combined our CT algorithms with emission measurements – mainly flame chemiluminescence images, and most recently with background-oriented schlieren measurements. We develop techniques for both laboratory settings, which are ideal for fundamental studies, and for the more challenging industrial environments where accessibility is almost always limited. We constantly develop and test our algorithms through various applications and phantom studies. A phantom is an exactly known field that can be compared to its reconstruction, allowing for a quantitative analysis of the reconstruction quality. We have followed the strategy of using realistic phantoms that represent the complexity of the fields that we try to reconstruct as well as possible. For this purpose we have often relied on large eddy simulation and direct numerical simulation data. If you would like to find out more about any of our tomography techniques, are interested in applying our techniques to an experiment, or would like to collaborate on innovative combinations of CT with different types of measurements please do not hesitate to contact us by sending an email to khadijeh.mohri@uni-due.de.

Events

Girl's day at UDE 2019’

Girlsday Photo

 

Collaborations

   Universities and research institutes

  1. University of Waterloo, Canada
  2. Nanjing University of Science and Technology (NJUST), China
  3. Hochschule Darmstadt, Germany
  4. Stanford University, USA
  5. TU Darmstadt, Germany
  6. Georgia Institute of Technology, USA

   Industry

  1. Continental, Germany
  2. Gas und Wärme Institute (GWI), Germany
  3. Siemens, Germany

 

Former students

  • Mr. Stanislaw Yaroshevskyy, Master thesis (2018): Design of a precision 3D camera mount.
  • Mr. Alexander Kassen, Bachelor thesis (2018): Adapting the tomographic setup to generate frozen flame movies for analysing the dynamics of a turbulent flame.
  • Mr. Andreas Unterberger, Master thesis (2018): 3D Evolutionary reconstruction of scalar fields: Phantom study and application to a stratified flame.
  • Mr. Manuj K. Yadav, Masters thesis (2017): Influence of low pressure exhaust gas recirculation (LP-EGR) on a turbocharger compressor - a numerical analysis
  • Mr. Julien Verbeke, Masters thesis (2017): Computed tomography of a swirl flame’s chemiluminescence field and LES-phantom study on effect of out-of-plane views

 

Journal publications

  1. A. Unterberger, J. Menser, A. Kempf, K. Mohri, Evolutionary Camera Pose Estimation of a Multi-Camera Setup for Computed Tomography, accepted by ICIP 2019 Conference Proceedings
  2. A. Unterberger, A. Kempf, K. Mohri, 3D Evolutionary Reconstruction of Scalar Fields in the Gas-Phase, Energies 12:11 (2019) 2075. https://doi.org/10.3390/en12112075
  3. A. Unterberger, M. Röder, A. Giese, A. Al-Halbouni, A. Kempf, K. Mohri, 3D instantaneous reconstruction of turbulent industrial flames using Computed Tomography of Chemiluminescence (CTC). Journal of Combustion special issue on Coal and Biomass Combustion 2018 (2018), doi: https://doi.org/10.1155/2018/5373829
  4. S. J. Grauer, A. Unterberger, A. Rittler, K. J. Daun, A. M. Kempf, K. Mohri, Instantaneous 3d flame imaging by background-orientated schlieren tomography. Combust. Flame 196 (2018) 284-299.
  5. Mohri, K., Görs, S., Schöler, J., Rittler, A., Dreier, T., Schulz, C., Kempf, A. M. (2017), Instantaneous 3D- imaging of highly turbulent flames using Computed Tomography of Chemiluminescence, Applied Optics 56, 7385-7395.
  6. A. Wohler, K. Mohri, C. Schulz and B. Weigand. Mixing processes in a compressible accelerated nozzle flow with blunt-body wakes. AIAA Journal (2014), doi: http://dx.doi.org/10.2514/1.J052493. Link
  7. K. Mohri, M. Luong, G. Vanhove, T. Dreier and C. Schulz. Imaging of the Oxygen distribution in an isothermal turbulent free jet using two-color toluene LIF imaging. Appl. Phys. B (2011) 103: 707-715. PDF Link
  8. K. Mohri and R. Hillier. Computational and experimental study of supersonic flow over axisymmetric cavities. Shock Waves (2011) 21: 175-191. PDF Link

 

Conference contributions

  1. A. Unterberger, J. Menser, A. Kempf and K. Mohri. Evolutionary camera pose estimation of a multi-camera setup for computed tomography. Oral presentation, 26th IEEE International Conference on Image Processing, Taipei, Taiwan (22-25 September 2019).
  2. J. Menser, A. Unterberger and K. Mohri. Convolutional neural networks for camera calibration requirements in flame tomography. Oral presentation at the 29th Deutscher Flammentag, Bochum, Germany (17-18 September 2019)
  3. J. Menser, A. Unterberger, L. Cifuentec, A. Kempf, K. Mohri. Quantifying flame tomography reconstructions with the aid of DNS phantom data. Poster at the 37th International Symposium on Combustion, Dublin, Ireland  (Jul.-Aug. 2018).
  4. A. Unterbeger, J. Menser, A. Kempf, K. Mohri. 3D evolutionary reconstruction of scalar fields: phantom study and application to a stratified flame. Poster at the 37th International Symposium on Combustion, Dublin, Ireland  (Jul.-Aug. 2018).
  5. K. Mohri, J. Menser, A. Kempf, J. Trabold, S. Walther, D. Geyer. Instantaneous 3D imaging of the Temperature Controlled Piloted Jet Burner (TCPJB) flames using computed tomography of chemiluminescence (CTC). Poster at the 37th International Symposium on Combustion, Dublin, Ireland  (Jul.-Aug. 2018).
  6. S. J. Grauer, A. Unterberger, T. A. Sipkens, A. M. Kempf, K. J. Daun. K. Mohri. Background-oriented schlieren tomography for instantaneous 3D combustion imaging. Poster at the 37th International Symposium on Combustion, Dublin, Ireland  (Jul.-Aug. 2018).
  7. J. Menser, A. Unterberger, A. Kemp and K. Mohri. Instantaneous 3D imaging of turbulent stratified methane/air flames using computed tomography of chemiluminescence. Oral presentation, 5th International Conference on Experimental Fluid Mechanics (ICEFM), Munich (Jul. 2018).
  8. J. Menser, A. Unterberger, S. Grauer, A. Kempf and K. Mohri. Volumetric imaging of turbulent stratified premixed flames using tomography, background-orientated schlieren and high-speed imaging. Poster, Centre for Nano Integration Duisburg-Essen (CENIDE) conference, Bergische Gladbach (Feb. 2018).
  9. K. Mohri, M. Röder, A. Giese, A. Al-Halbouni and A. Kempf. 3D instantaneous reconstruction of a turbulent industrial burner flame using Computed Tomography of Chemiluminescence (CTC). Oral presentation, 3rd General Meeting and Workshop on SECs in Industry COST Action 1404 of the European Cooperation in Science and Technology, Prague (Oct. 2017).
  10. K. Mohri, M. Röder, A. Giese, A. Al-Halbouni, A. Kempf. Computed Tomography of Chemiluminescence (CTC): reconstructing turbulent laboratory and industrial flames. Poster, 28th Deutscher Flammentag, Darmstadt (Sep. 2017).
  11. J. Verbeke, A. Rittler, S. Görs, C. Schulz, A. Kempf and K. Mohri. Computed Tomography of Chemiluminescence (CTC): Effect of out-of-plane views on the quality of three-dimensional reconstruction of a turbulent swirl flame. Poster and paper, 8th European Combustion Meeting, Croatia, April 2017.
  12. K. Mohri, S. Görs, J. Schöler, T. Dreier, C. Schulz and A. Kempf. Tomographic reconstruction of the highly turbulent TECFLAM and unsteady Bunsen flames’ 3D instantaneous chemiluminescence field. Poster, 36th International Symposium on Combustion (2016).
  13. K. Mohri, A. Kempf. Computed tomography of chemiluminescence in asymmetric unsteady premixed flames. Poster and paper, 27th Deutscher Flammentag, VDI-Berichte Nr. 2267 (2015) 729-734.
  14. K. Mohri and A. Kempf. Computed tomography of chemiluminescence for 3D reconstructions of quasi-steady premixed flames. Talk and poster, Combustion Institute (British section) meeting, Imperial College London (2014).

 

Multi-camera Tomography Setup

    Bos Bunsen

Background-Oriented Schlieren Tomography (BOST)

    Bos Bunsen

Computed Tomography of Chemiluminescence (CTC)

Reconstruction of the instantaneous 3D chemiluminescence field of a highly turbulent swirl-stabilised flame (equivalence ratio ɸ = 1.0).

   Mohri Flame Reconstruction Arb

Cross-sectional slices of the reconstructed instantaneous 3D chemiluminescence field of the swirl flame (equivalence ratio ɸ = 1.0), at different heights above the burner z normalised by the burner bluff body diameter DT.

Evolutionary Reconstruction Technique (ERT)

   Ert Stratified Chemlum Rec