Effect of absorption depth on chemical energy release from laser ablation of ADN-based liquid propellants

Ammonium dinitramide is a new green oxidant, which has been widely used in the field of liquid propulsion. In order to study the influence of doping laser absorber on the propulsion performance of liquid targets, the mixed solution of ammonium dinitramide and ionic liquid 1-allyl-3-methylimidazolium dicyandiamide was used as the ablation target, and the infrared dye was used as the laser absorber to change the doping content of infrared dye and laser energy density. The results show that the light absorption performance of liquid propellant is obviously improved with the increase of infrared dye content. The absorption coefficient and absorption depth of liquid propellant with infrared dye content of 0.6wt% are 425.19 cm−1 and 23.52 μm, respectively. The propellant with lower absorption depth produces high values of impulse bit, specific impulse, impulse coupling coefficient and ablation efficiency under the ablation of high laser energy density. The propellant sample doped with 0.6wt% infrared dye yielded the highest impulse bit of 114.32 μN·s, largest specific impulse of 84.14 s, highest impulse coupling coefficient of 1.07 mN·s·J−1, and the maximal ablation efficiency of 44% at the laser energy density of 21.51 J·cm−2. Furthermore, the effects of laser energy density and absorption depth on the chemical energy release of liquid propellant were studied. It was found that the maximum contribution of chemical energy to kinetic energy of ammonium dinitramide based liquid propellant is 93.93%. In general, improving the absorption performance of propellant can significantly enhance the energy release of energetic propellant. Which has guiding significance for propellant design and selection.