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Diagnostics optiques capables de localiser la formation de NO dans les moteurs Diesel : Fluorescence par plan laser sur deux raies atomiques; Chimiluminescence de l'oxyde de bore

Abstract : The reduction of the NOx emissions in engines is of critical interest for the automotive industry. The main formation pathway of NO at high temperatures is the Zeldovich mechanism which rate of the limiting initiation step N2+O->NO+N is strongly increasing with temperature. The formation of thermal NO comes then from the local conjunction of high temperature and high concentration of atomic oxygen. In the present work, two optical diagnostics are studied to map the temperature and NO formation rate.
A thermometry technique based on Two-Line Atomic Fluorescence of seeded indium atoms in a two-dimensional planar imaging mode was performed. The two transitions were not excited successively. The reference temperature measurement is obtained in a premixed flame. The TLAF temperature measurements show good agreements with thermocouple measurements in soot-free flame regions and in sooting regions where thermocouple is unsuitable.
A flame seeded by boron salts shows the green chemiluminescence of boron dioxide, chemically created on its excited state according to the reaction BO+O-> BO2*, which depends on the concentration of atomic oxygen and on the temperature in a similar way as the formation of nitric oxide does. In premixed flames, the spectroscopic studies show reasonable agreement between BO2* chemiluminescence and calculated formation rate of thermal NO from the PREMIX code of CHEMKIN, despite some reserve for fuel rich premixed flames. In diffusion flames for two dimensional imaging mode, both BO2* emissions location and computed thermal NO profile take place in high temperature regions (T>1800K).
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Submitted on : Wednesday, January 30, 2008 - 8:22:43 AM
Last modification on : Tuesday, February 5, 2019 - 11:44:12 AM
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  • HAL Id : tel-00223973, version 1

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David Maligne. Diagnostics optiques capables de localiser la formation de NO dans les moteurs Diesel : Fluorescence par plan laser sur deux raies atomiques; Chimiluminescence de l'oxyde de bore. Energie électrique. Université de Rouen, 2007. Français. ⟨tel-00223973⟩

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