MBMS ANALYSIS OF A FUEL-LEAN ETHYLENE FLAME

A one-dimensional laminar C2H4/O-2/Ar flame was analyzed with a molecu lar-beam mass spectrometer (MBMS) system. Profiles of concentration, a rea expansion ratio and temperature were measured for a C2H4O2/56.9% A r (phi = 0.75) flame at 4.000 +/- 0.001 kPa (30.00 Torr) and 30.0 cm/s burner velocity (at 300 K). Full concentration profiles were mapped f or 22 stable and radical species, while point measurements were made f or seven other species. These mole fraction data are valuable for infe rence of kinetics and testing of reaction mechanisms. Elemental flux d eviations were less than 15% in the flame zone and less than 3% in the post-flame zone supporting the data's accuracy and reliability. Flux balance calculations were also used to obtain the net rate of destruct ion for C2H4 and C2H3. New values of the rate constants for C2H4 + H - -> C2H3 + H-2, C2H4 + OH --> C2H3 + H2O and C2H3 --> C2H2 + H were sup ported by the agreement between measured rates and the rates predicted from measured temperatures, measured mole fractions, and the new rate constants. (C) 1998 by The Combustion Institute.