Shock tube study of reactions of C atoms and CH with NO including product channel measurements. (Reannouncement with new availability information)

Technical Report · Tue Dec 31 04:00:00 EST 1991

OSTI ID:121812

Dean, A J; Hanson, R K; Bowman, C T

The reactions of C atoms and CH with NO, which are believed to be initial steps in the NO reburning reaction mechanism, were studied at high temperature behind reflected shock waves. C atoms were formed by pyrolysis or photolysis of dilute mixtures Of C302 in argon or by pyrolysis of dilute mixtures of CH4 in argon. CH was formed from the pyrolysis of dilute mixtures of CH4 or C2H6 (<30 ppm) in argon. C atoms were detected by use of atomic resonance-absorption (ARAS) at 156.1 nm. CH was detected by CW, narrow-line-width laser absorption at 431.131 nm. In the presence of excess NO, C atoms formed by pyrolysis or photolysis rapidly were removed by C(3p) + NO - products (1). A first-order kinetic analysis led to a rate coefficient k1 = 4.8 X 10 to the 13th power (+ or - k45%) cu cm/mol/s over the temperature range 1550-4050 K and pressure range 0.5-1 atm. In order to determine the rate coefficient of CH(X2II) + NO - products (2), a perturbation technique was employed. In this technique, the CH concentration profile resulting from pyrolysis of CH4 or C2H-diluted in argon was perturbed by the addition of NO. A detailed analysis of the CH profiles led to the rate coefficient k2 = 1.0 x 10 to the 14th power (+ or - 50%) cu cm/mol/s over the temperature range 2570-3790 K and pressure range 0.6-1.1 atm. The product channels of reactions 1 and 2 were studied by measuring the formation of product species, CN, N atoms, O atoms, OH, and NH, using laser absorption or ARAS. The branching ratios of the product channels of reaction 1, C(3P) + NO - CN + O (la) and C(3p) + NO - CO + N (lb), are k1b/k1 = 40% and klb/kl = 60%. independent of temperature from 2430 to 4040 K.

• Research Organization: Stanford Univ., CA (United States). Dept. of Mechanical Engineering
• OSTI ID: 121812
• Report Number(s): AD-A--246978/1/XAB; CNN: Grant AFOSR-89-0067
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
CARBON
COMBUSTION KINETICS
HYDROCARBONS
MIXTURES
NITRIC OXIDE
REACTION KINETICS
RESONANCE ABSORPTION
SHOCK TUBES
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K