A Study of the Ignition Kinetics of XM46

Abstract

Preliminary results in an attempt to define the ignition kinetics of the liquid propellant XM46 under high-heating rates are reported. Three methods of approach have been applied: (1) conventional differential scanning calorimetry (DSC), (2) a drop of the liquid floating in an inert, heated liquid, and (3) C0 2 laser heating. In the latter case, the delay to pressure release has been studied as a function of prepressurization over the range from 3 to 14 Mpa (500 to 2,000 psi). Expressed as delay (ms) = Cexp(E/RT), values measured are C = 2.48 and 2.45 and E a = 7.7 (±4.9) and 1.9 (+1.2) kcal/mol at pressures of 6.9 Mpa (1,000 psi) and 9.7 Mpa (1,400 psi), respectively. The temperature of the liquid used for analysis of the laser heating experiments is calculated. The ignition (reaction) delays show a strong temperature and pressure dependence. High-speed photography shows that the pressure rise is not from ignition of the small volume where the energy is absorbed, but is rather from a partial reaction involving most of the liquid in the vessel.n