Ignition and combustion studies on metallized UDMH-RFNA bipropellant system

Abstract

The ignition delay studies on unsymmetrical dimethyl hydrazine gelled with methyl cellulose (4.48 wt%) containing varying amounts of metal powder (Al and Mg) with red fuming nitric acid oxidant have been carried out at and around oxidizerfuel(O/F)<i> </i>ratios corresponding to maximum specific impulse. The minimum ignition delay is registered at a critical O/F ratio which is always less than the respective stoichiometric mixture ratios. Further, the ignition delay is related with theoretical specific impulse and are both found to be inversely related with each other. The minimum ignition delay and critical O/F ratio

have been found to vary linearly with metal content of fuel gel. The data on 'heat of combustion' show that it increases linearly with the degree of metallization of gelled fuel and experimental value of 'heat of combustion' is found to be less than its theoretical value. The analysis of data show that the oxide formation in case of aluminium occurs mainly by water vapour-metal

<span style="font-size:14.0pt;line-height:115%;font-family:" times="" new="" roman";="" mso-fareast-font-family:"times="" roman";color:black;mso-ansi-language:en-in;="" mso-fareast-language:en-in;mso-bidi-language:hi"="" lang="EN-IN">interaction and marginally due to direct oxidizer-metal reaction whereas for the oxidation of magnesium only the former mechanism seems to be operative.</span>