COBEM99

SR4 Combustão

Title:

ON THE CHARACTERIZATION OF AIR/FUEL MIXTURE DISTRIBUTION THROUGH C2/CH CHEMILUMINESCENCE RATIO IN A LPP COMBUSTOR

Summary :

THIS PAPER DISCUSSES THE UTILISATION OF C2/CH CHEMILUMINESCENCE RATIO AS A DIAGNOSTIC TECHNIQUE TO ASSESS MIXTURE NON-HOMOGENEITIES WITHIN LIQUID FUEL LEAN PREMIXED FLAMES BURNING INSIDE A LABORATORY SCALE MODEL OF A LPP COMBUSTION CHAMBER. C2 AND CH MONOCHROMIC PROJECTIONS ARE TOMOGRAPHICALLY RECONSTRUCTED TO OBTAIN THEIR THREE-DIMENSIONAL DISTRIBUTION, WHICH ALLOWS THE SPATIAL CORRELATION OF C2 AND CH FIELDS AT SEVERAL GASEOUS AND LIQUID FUEL EQUIVALENCE RATIO/VANES ANGLE COMBINATIONS. THE INFLUENCE OF VANES ANGLE DEPICTS THAT NON-SWIRLING FLAME IS BLUFF-BODY STABILISED, AND AS THE SWIRL INCREASES, A NEW RECIRCULATION ZONE IS INDUCED, BENDING THE FLAME AND CONCENTRATING THE REACTION ZONE WITHIN THE FIRST SECTION OF THE COMBUSTION CHAMBER. THE RELATIONSHIP BETWEEN C2/CH RATIO AND EQUIVALENCE RATIO FOR PROPANE FLAMES SHOWS THAT INTENSITY RATIO INCREASES SIMULTANEOUSLY WITH EQUIVALENCE RATIO, AS WELL AS THE DIFFERENCE BETWEEN THE MAXIMUM AND MINIMUM VALUES OF C2/CH RATIO, PROBABLY DUE TO INCOMPLETE MIXING. THE UTILISATION OF LOCAL C2/CH RATIO IS THEREFORE RELATED TO EQUIVALENCE RATIO AND CAN ASSESS USEFUL INFORMATION ON THE QUALITY OF THE MIXING PROCESS. THE PRESENT RESULTS PROVIDE NEW INFORMATION ON THE CHARACTERISATION OF MIXTURE HOMOGENEITY OF LEAN PREMIXING FLAMES WITHIN PRACTICAL COMBUSTION CHAMBER GEOMETRY. THE RESULTS REINFORCE THE QUALITATIVE COMPROMISE BETWEEN LIGHT INTENSITY AND MIXING CONDITIONS.

Author :

Anacleto, Paulo 0
Caldeira-Pires, Armando 0
Costa, Fernando de Souza
Lacava, Pedro Teixeira

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