Laser Ignition of Different Aluminum Nanopowders for Solid Rocket Propulsion

Aluminum nanopowders (nAl) coated with oleic acid (nAl@OA), perfluorotetradecanoic acid (nAl@PA) and nickel acetylacetonate (nAl@NA) were prepared. The ignition and combustion characteristics of different aluminum nanopowders were studied using the laser ignition system. And the combustion characteristics of hydroxyl-terminated polybutadiene (HTPB)-based composite solid propellants containing different coated aluminum nanopowders were also investigated. The results show that there is a critical power of laser heat flux density in the ignition process of the coated aluminum nanopowders. The ignition delay time of nAl@NA is shorter than that of nAl@PA and nAl@OA, because of the combustion catalysis of nickel acetylacetonate. The burning rate of the propellant sample containing nAl@NA is the highest among all the formulations at different pressure ranges, and the maximum burning rate is up to 26.13 mm.s(-1) at 15 MPa. The burning rates of propellant samples containing nAl@OA and nAl@PA are almost the same at different pressures and higher than that of the propellant samples containing untreated aluminum nanopowders only at the pressure range of 10-15 MPa. The flame intensity of different propellants at different pressure is not the same. Moreover, the surface coated aluminum nanopowder has a little effect on the combustion flame temperature of solid propellant. The burning surface temperature of propellant increases with an increase in pressure.