Experimental Investigation of Ramburner Performance. Part I. Liquid Propellant Runs

This report describes the results of a series of connected-pipe runs with an air-augmented rocket system burning liquid rocket propellants. The liquid propellant runs served to evaluate the behavior of the facility and instrumentation with regard to accuracy and to provide performance data for combustion where the chemical rate processes were relatively fast compared with those of metal combustion. The ramburner was designed to provide axisymmetric, coaxial mixing of the primary and secondary streams in a constant area duct. No mixing aids were employed. Nitrogen tetroxide and Aerozine-50 served as the rocket propellants. The secondary air was preheated by combustion to a nominal temperature of 1100 R to simulate flight stagnation conditions. Runs were made with nominal pressures in the ramburner of 90 and 175 psia. The air/propellant ratio was varied from 5 to 13 (approximately 250 to 600 percent theoretical air). Two oxidizer-to-fuel ratios were employed for the primary rocket: 0.8 (fuel rich) and 2.0 (stoichiometric). Combustion efficiencies between 75 and 90 percent were observed for the complete system, decreasing with increasing air/propellant ratio. Estimated uncertainties in the efficiency values were + or - 3 percent. Ramburner efficiencies tended to be 10 to 15 percent lower and were subject to uncertainties in the neighborhood of + or - 6 percent. A slight decrease in efficiency with decreasing pressure was also observed. (Author) See also Part 2, AD-523 198.