Al-water fed chemically augmented DC arcjet characteristics

In this study, development of Al-water fed arcjet was conducted, in which water and aluminum were fed to the thruster as the propellant. Numerical investigations based on chemical equilibrium calculations were conducted to understand the details of combustion reactions and products of the electrically augmented aluminum and water reactions. From the chemical equilibrium simulation, it was shown that thrust performance of the Al-water fed arcjet was as well as that of hydrazine arcjets at low specific power range. In addition, to observe behaviors of vaporized aluminum propellant fed as a solid state rod to the arcjet and then vaporized in the discharge plenum, a novel coaxial double cathode was developed and tested. From hispeed camera images, it was shown that streams of vaporized aluminum were injected through the injection holes at a tip of the coaxial double cathode. From the spectroscopic diagnostics of the plasma in the plenum, it was confirmed that injected vapor from the injectors of the coaxial double cathode was mainly vaporized aluminum