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A recently developed research apparatus for characterization of low-pressure premixed flames has been developed and was used to characterize the C2H4/N2O/Ar flame at 20 torr. This instrument incorporates several diagnostic techniques in one apparatus so that individual techniques can be quantitatively compared and the usable detection range (both in terms of resolution and species detection) expanded. Results discussed in this report include mass analysis by triple quadrupole mass spectrometer and temperature measurement by thermocouple. Concentration profiles in the one-dimensional flame include CO, N2, and C2H4, at nominal m/z 28 as well as CO2 and N2O at m/z 44.

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

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