Photochemical Ignition of Gaseous Fuel-Oxidizer Mixtures at Subatmospheric Pressures,
Abstract
Experimental results are presented on the radiative initiation of sustained combustion in unsensitized, stoichiometric mixtures of methane-oxygen, methane-air, hydrogen-oxygen and hydrogen-air at room temperature and at fuel-oxygen partial pressures from 25 to 600 torr. Minimum irradiance required to photochemically induce ignition, photochemical ignition delay time and reaction front propagation velocity were measured as a function of reactant mixture pressure. Delay times of 0.1 to 1.0 msec were measured for the photochemical initiation of sustained combustion under pressure-temperature conditions where thermal ignition does not occur. The primary initiation mechanism is shown to be photodissociation of oxygen by radiation in the Schumann-Runge continuum (1350-1700 A), a region still inaccessible to laser sources. Generation of a critical concentration of atomic oxygen is a necessary precondition for ignition. Because the initiation mechanism is found to be independent of fuel type, applications are suggested to many fuel-air systems of practical interest. Fundamentally, this unprecedented photochemical initiation of sustained combustion of unsensitized fuel-air mixtures represents a promising new departure in the field of combustion. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1969
- Accession Number
- AD0861320
Entities
People
- A. E. Cerkanowicz
- M. Levy
- R. F. Mcalevy Iii