1. Experimental assessment of the sudden-reversal of the oxygen dilution effect on soot production in coflow ethylene flames II: soot radiation and flame transition analysis
- Author
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Weiwei Cai, Guillaume Legros, Jean-Louis Consalvi, Céline Morin, Fengshan Liu, Qianlong Wang, Haifeng Liu, State Key Laboratory of Engines, Tianjin University, Tianjin, Institut universitaire des systèmes thermiques industriels (IUSTI), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Automatique, de Mécanique et d'Informatique industrielles et Humaines - UMR 8201 (LAMIH), Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-INSA Institut National des Sciences Appliquées Hauts-de-France (INSA Hauts-De-France), Sorbonne Université (SU), Measurement Science and Standards, National Research Council of Canada, Ottawa, Ontario, Canada, Key Lab of Education Ministry for Power Machinery and Engineering, School of Mechanical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China, State Key Laboratory of Engines, Tianjin University, Tianjin, 300072, China, and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)
- Subjects
Materials science ,010504 meteorology & atmospheric sciences ,Analytical chemistry ,chemistry.chemical_element ,medicine.disease_cause ,01 natural sciences ,Oxygen ,complex mixtures ,soot ,[SPI]Engineering Sciences [physics] ,fluids and secretions ,Radiative transfer ,medicine ,Spectroscopy ,0105 earth and related environmental sciences ,ethylene diffusion flames ,Radiation ,Diffusion flame ,Laminar flow ,[SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph] ,flame transition ,smoking flames ,Atomic and Molecular Physics, and Optics ,Soot ,humanities ,Dilution ,local radiative intensity field ,chemistry ,13. Climate action ,Volume fraction ,Intensity (heat transfer) - Abstract
The current study focuses on the radiative characteristics of heavy smoking flames that are formatted by oxygen being added to the fuel stream of a steady laminar ethylene diffusion flame. In such a scenario, based on the experimental local soot temperature and volume fraction results, the soot local radiative fields are obtained by solving the Radiative Transfer Equation (RTE). Along with the diluted range (oxygen volume fraction X O 2 a x from 0 to 32%), the flame undergoes two significant transitions, i.e., smoking and non-smoking; however, only one remarkable radiative intensity transition between 30% and 32% is identified. The radiative loss due to the oxygen chemical effect is further assessed by comparing with that of N2 diluted flames. It is found that the chemical effect on radiative loss promotion is undermined by approximately 25%, compared with that on soot formation promotion. In contrast, the oxygen dilution effect results in a similar reduction level on soot formation propensity and soot radiative loss. Furthermore, the correlations between relative soot consumption rate and cumulated radiative loss below the flame tip region are explored, and the results indicate that the initial relative oxidation rate at the position of z F v , max (the peak location of flame cross-section mean soot volume fraction) and its residence time are two important factors that may affect the final flame smoking/non-smoking transition. Eventually, these local soot radiative intensity fields, together with the local soot temperature and volume fraction fields, provide a more comprehensive benchmark to refine the soot oxidation model as the ISF workshop required and understand the flame transition mechanism in the sooting flames.
- Published
- 2020