Accession Number : ADA299717

Title :   High Temperature Reaction Kinetics of Boron Oxides.

Descriptive Note : Final rept. 15 Jun 91-30 Sep 94,

Corporate Author : ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER

Personal Author(s) : Twarowski, Allen J.

PDF Url : ADA299717

Report Date : AUG 1994

Pagination or Media Count : 14

Abstract : Kinetics experiments performed under this contract show a much larger rate of H+OH recombination at high temperature (1500-2500K ) when phosphine combustion products are present in the gas mixture. A kinetic mechanism has been developed for phosphorus species participation in the reaction chemistry. This mechanism has been used to fit both OH decay signals and H2O hot band absorbance signals in H2O laser photolysis experiments. The temperature dependence of the phosphorus reaction system was measured with laser photolysis experiments and a sensitivity analysis selected the key chemical reactions that drive H+OH recombination (and H+H recombination) in phosphorus species-containing gases. Rate constants for phosphorus bimolecular reactions were estimated using standard kinetics assumptions. Rate constants for recombination reactions were estimated using a simplified version of RRKM theory. Agreement between OH decay measurements in photolysis experiments and computed OH time profiles using the phosphorus mechanism developed in this contract is reasonably good. Computer simulations of SCRAM-jet nozzle gas flow using 1-D hydrodynamics coupled with the phosphorus kinetic mechanism show a large increase in heat release per unit fuel mass in the nozzle when phosphine is included in hydrogen fuel. These same computer calculations predict a net increase in fuel specific impulse under fuel rich conditions. Optimization of nozzle design for hydrogen fuel with a phosphine additive may realize even more gain in specific Impulse.

Descriptors :   *REACTION KINETICS, *HIGH TEMPERATURE, *HYDROGEN, *PHOSPHORUS, *BORON OXIDES, THERMAL PROPERTIES, COMPUTERIZED SIMULATION, MEASUREMENT, OPTIMIZATION, COMPUTATIONS, PHOTOLYSIS, MOLECULES, MASS, ONE DIMENSIONAL, RATES, LASERS, GASES, MIXTURES, TIME, FUELS, PROFILES, RESPONSE, SIGNALS, CHEMICAL REACTIONS, CONSTANTS, RELEASE, NOZZLES, COMPUTER APPLICATIONS, ADDITIVES, KINETICS, RECOMBINATION REACTIONS, PHOSPHINE, HEAT, SUPERSONIC COMBUSTION RAMJET ENGINES, HYDRODYNAMICS, DECAY, MOLECULAR PROPERTIES, JET FLOW, SPECIFIC IMPULSE, HYDROXYL RADICALS, COMBUSTION PRODUCTS.

Subject Categories : Inorganic Chemistry
      Physical Chemistry
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE