Flames, adjustment burning velocities

Another important feature of this analysis was that for fixed values of fei 7, and for the imposed condition of satisfactory prediction of measured burning velocities, the H atom concentration profiles in specific flames were not appreciably affected by the particular combination selected from the adjustable parameters concerned with reactions (viii), and (xviii)— (xxii), i.e. the rate coefficients g and ftj 9, and the ratios ftga/fegi ( a fesa)/ 2 0> 21/ 20 and 2 2/ 20- This implies that, despite somewhat incomplete characterization at this stage, the flame and the computational approach may be used to study the reactions of its radical species with trace additives. Such an analysis with D2O, D2 and CO2 as the trace additives, has been used by Dixon-Lewis [172] to obtain information about the rate coefficients fe j d a. 1 2 3 >... 

Fig. 2a. Premixed flames. With premixed flames many geometries are possible depending on the inlet gas flow profile. The flame can be considered as a thin reaction sheet which adjusts itself so that at every point the component of incoming gas velocity normal to the flame front is exactly balanced by the burning velocity (see Fig. 1). Several geometries which have been used in laboratory studies are illustrated. Courtesy of Applied Physics Laboratory, The Johns Hopkins University.

The structure of the flame comprises an inner cone, which is the primary reaction zone for combustion, and the outer cone or mantle where secondary reactions occur. For the best results, the optical axis is arranged to pass through the flame at the junction of the inner and outer cones. The supply of fuel and oxidant is adjusted to give an optimum burning velocity. 

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