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TURBULENT COMBUSTION AND DIAGNOSTICS - ROTATIONAL AND VIBRATIONAL ANALYSIS OF OH LIF IN ATMOSPHERIC PRESSURE HYDROCARBON FLAME.

Objective

RESEARCH COORDINATED BY HARWELL COMBUSTION CENTRE IN THE FRAME OF THE CONTRACT EN3E008800.
THE MAIN OBJECTIVES IS TO PERFORM ROTATIONALLY RESOLVED OH LIF MEASUREMENTS IN ATMOSPHERIC PRESSURE FLAME - TO DEVELOP NUMERICAL MODELS FOR ROTATIONAL, VIBRATIONAL ENERGY TRANSFER AND QUENCHING. TO FIT THE NUMERICALLY CALCULATED AND THE EXPERIMENTALLY DETERMINED LEVEL POPULATIONS IN ORDER TO OBTAIN SPACIALLY RESOLVED AND INSTANTANEOUS TEMPERATURE AND CONCENTRATION MEASUREMENTS IN FLAME.

A SURFACE MIXING LABORATORY BURNER FOR THE PRODUCTION OF ATMOSPHERIC PRESSURE FLAMES, WILL BE DEVELOPED. CH4 AND C2H2 BASED FLAMES WITH VARIOUS STOICHIOMETRIES, WILL BE CHARACTERIZED BOTH IN TEMPERATURE AND OH TOTAL NUMBER DENSITIES. ROTATIONALLY RESOLVED LIF SPECTRA WILL BE MEASURED AT SUITABLE LOCATIONS IN THE FLAME BY PUMPING SEVERAL ROTATIONAL LEVELS IN THE V=0 AND V=1 VIBRATIONAL MANIFOLDS. THE SPECTRA WILL BE ANALYZED TO EXTRACT THE POPULATION DISTRIBUTION IN THE EXCITED STATE. A STEADY STATE NUMERICAL MODEL OF THE POPULATION COLLISIONAL REDISTRIBUTION WILL BE CONSTRUCTED, BASED UPON LITERATURE AVAILABLE CROSS SECTIONS OF COLLISIONAL ENERGY TRANSFER AND DIFFERENT SCALING LAWS. FITTING THE NUMERICAL DISTRIBUTIONS WITH THE EXPERIMENTAL ONES WILL GIVE THE POSSIBILITY OF MEASURING THE FLAME TEMPERATURE ON A SINGLE SHOT BASIS. THE APPLICATION OF THE COLLISIONAL RELAXATION MODELS TO THE GROUND STATE RELAXATION WILL ALLOW A COMPLETE DESCRIPTION OF THE OH LASER EXCITED DYNAMICS. TOTAL NUMBER DENSITIES WILL BE DERIVED AND COMPARED WITH VALUES OBTAINED BY ABSORPTION MEASUREMENTS.FURTHER REFINEMENTS WILL REQUIRE THE APPLICATION OF THE SPACIALLY RESOLVED ABSORPTION TECHNIQUE. TENTATIVELY AN ANALYSIS OF THE EFFECTIVE ROTATIONAL AND VIBRATIONAL RELAXATION IN THE GROUND STATE WILL BE ATTEMPTED.
THE ACTIVITIES ABOVE WILL BE PERFORMED ACCORDING TO THE FOLLOWING "WORK PACKETS".

STAGE 1 : CHARACTERIZATION OF STANDARD FLAMES PRODUCED BY A SURFACE MIXING BURNER.
STAGE 2 : OH LASER EXCITED FLUORESCENCE MEASUREMENTS DETERMINATION OF THE LEVEL POPULATION DISTRIBUTION.
STAGE 3 : NUMERICAL MODELS FOR OH RELAXATION
STAGE 4 : OH TOTAL NUMBER DENSITY DETERMINATION.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Consiglio Nazionale delle Ricerche (CNR)
Address
Via Francesco Baracca 69
20068 Peschiera Borromeo Milano
Italy

Participants (1)

United Kingdom Atomic Energy Authority (UKAEA)
United Kingdom
Address
Harwell Laboratory
OX11 0RA Didcot