Combustion behavior and flame structure of XM46 liquid propellant

This investigation was focused on the combustion behavior of XM46. The regr ession rate of XM46 has been characterized up to 207 MPa, displaying a comp lex burning behavior with both negative pressure exponent and plateaulike b ehavior. The dame structure displayed three different stages: 1) nearly sim ultaneous decomposition of both hydroxylammonium nitrate (HAN) and thirthan ol ammonium nitrate initiating in the liquid to produce gases around 300 de greesC, 2) breakdown of heavy opaque intermediate molecules into transparen t species, and 3) reaction of transparent species to form final products in the luminous dame, The feeding tests showed peculiar flashback phenomena, belie,ed to be related to the interaction between gas-phase radicals and un burned liquid propellant. Pyrolysis tests of XM46 were conducted in a speci ally designed pyrolyzer used in conjunction with a gas chromatograph/mass s pectrometer, The major pyrolysis products observed were NO, N2O, N-2, CO2, CO, H2O, HCN, and C2H4 when pyrolyzed at temperatures between 130 and 540 d egreesC. The pressure dependency of the burning rate of the MAN-based liqui d propellant is highly nonlinear, Water evaporation has a noticeable effect on combustion characteristics of XM46. Gas dissolution/desorption could al so affect the burning rate. The type of fuel ingredient was found to have a significant effect on the overall burning characteristics.