Thermal Stability of RP-2 as a Function of Composition: The Effect of Linear, Branched, and Cyclic Alkanes
Thomas J. Bruno, Jason A. Widegren
The objective of this work was to identify compositional changes that could improve the thermal stability of the kerosene rocket propellant known as RP-2. For this study, we tested the effect of different types of alkanes on the thermal stability of RP-2. The proportion of linear, branched or cyclic alkanes was increased by mixing RP-2 with 25 % (by mass) of one of the following alkanes: n-dodecane, n-tetradecane, 4-methyldodecane, 2,6,10-trimethyldodecane, or 1,3,5-triisopropylcyclohexane. These mixtures were thermally stressed in stainless steel ampoule reactors at 673 K (400 °C, 752 °F) for up to 4 hours. All of the reactions were run with an approximate initial pressure of 34.5 MPa (5000 psi). After each reaction, the stressed fuel was analyzed by gas chromatography with flame ionization detection. The decomposition kinetics of each added alkane was determined from the decrease in its chromatographic peak. The overall decomposition kinetics of each fuel mixture was determined from the increase in a suite of chromatographic peaks that correspond to light decomposition products. These data are compared to similar data for neat RP-2.