Analytical study of the hydrogen-air reaction mechanism with application to scramjet combustion
A chemical kinetic mechanism for the combustion of hydrogen has been assembled and optimized by comparing the observed behavior as determined in shock tube and flame studies with that predicted by the mechanism. The reactions contained in the mechanism reflect the current state of knowledge of the chemistry of the hydrogen/air system, and the assigned rate coefficients are consistent with accepted values. It was determined that the mechanism is capable of satisfactorily reproducing the experimental results for a range of conditions relevant to scramjet combustion. Calculations made with the reaction mechanism for representative scramjet combustor conditions at Mach 8, 16, and 25 showed that chemical kinetic effects can be important and that combustor models which use nonequilibrium chemistry should be used in preference to models that assume equilibrium chemistry. For the conditions examined the results also showed the importance of including the HO/sub 2/ chemistry in the mechanism. For Mach numbers less than 16, the studies suggest that an ignition source will most likely be required to overcome slow ignition chemistry. At Mach 25, the initial temperature and pressure was high enough that ignition was rapid and the presence of an ignition source did not significantly affect reaction rates.
- Research Organization:
- National Aeronautics and Space Administration, Hampton, VA (USA). Langley Research Center
- OSTI ID:
- 5307500
- Report Number(s):
- N-88-15846; NASA-TP-2791; L-16372; NAS-1.60:2791
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
42 ENGINEERING
HYDROGEN
KINETICS
CHEMICAL REACTIONS
COMBUSTION
FLAMES
IGNITION
MACH NUMBER
MATHEMATICAL MODELS
RAMJET ENGINES
SHOCK TUBES
ELEMENTS
ENGINES
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
NONMETALS
OXIDATION
THERMOCHEMICAL PROCESSES
VELOCITY
400800* - Combustion
Pyrolysis
& High-Temperature Chemistry
421000 - Engineering- Combustion Systems