Ignition and combustion studies on metallized UDMH-RFNA bipropellant system

摘要

The ignition delay studies on unsymmetricaldimethyl hydrazine gelled with methyl cellulose (4.48wtpercent)containing varying amounts of metal powder (Al and Mg) with redfuming nitric acid oxidant have been carried out at and aroundoxidizer-fuel (O/F) ratios corresponding to maximum specificimpulse. The minimum ignition delay is registered at a critical O/Fratio which is always less than the respective stoichiometricmixture ratios. Further, the ignition delay is related withtheoretical specific impulse and are both found to be inverselyrelated with each other. The minimum ignition delay and criticalO/F ratio have been found to vary linearly with metal content offuel gel. The data on 'heat of combustion' show that it increaseslinearly with the degree of metallization of gelled fuel andexperimental value of 'heat of combustion' is found to be less thanits theoretical value. The analysis of data show that the oxideformation in case of aluminium occurs mainly by water vapour-metal interaction and marginally due to direct oxidizer-metalreaction whereas for the oxidation of magnesium only the formermechanism seems to be operative.