ISSN 2079-3537      

 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                             





Scientific Visualization, 2021, volume 13, number 4, pages 1 - 8, DOI: 10.26583/sv.13.4.01

Polychromatic Diagnostics of the Flame with Hilbert Verification of the Visualized Phase Structure

Authors: Yu.N. Dubnishchev1,A,C, V.A. Arbuzov2,A,C, E.V. Arbuzov3,A,B,C, O.S. Zolotukhina4,A,C, V.V. Lukashov5,A

A Kutateladze Institute of Thermophysics of the Siberian Branch of the Russian Academy of Sciences

B Sobolev Institute of Mathematics of the Siberian Branch of the Russian Academy of Sciences

C Novosibirsk State Technical University

1 ORCID: 0000-0001-7874-039X, dubnistchev@itp.nsc.ru

2 ORCID: 0000-0003-2404-326X

3 ORCID: 0000-0001-9488-8650

4 ORCID: 0000-0003-3486-4459

5 ORCID: 0000-0001-8178-7607

 

Abstract

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. The method based on polychromatic Hilbert visualization of the phase optical density fields induced by the temperature field in the studied medium, pixel-by-pixel processing of RAW images recorded by the photomatrix in RGB channels, and Hilbert verification of the results is presented with an example of studying an axisymmetric hydrogen-air diffusion flame. 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.

 

Keywords: Optical diagnostics of a flame, hydrogen-air diffusion flame, Hilbert optics.