Low-power Water Arcjet Stability Study

At present, arcjet has been the highlight of investigation and application because of its high thrust density, high ratio of thrust and power, preferable specific impulse, better system successiveness and reliability. Arcjet which used water as propellant has special advantage in deep space exploration and manned spacecraft. In the research of water arcjet, serious oscillation existed in jet and arc voltage was found and it led to unstable work state of arcjet. Solution of instability of water arcjet has important significance to its development and application.Our research found that, the main reason which led to the oscillation of jet and arc voltage was the oscillation of propellant flowrate. The oscillation of flowrate was caused by the oscillation of water evaporation in pipes. In this paper, the principle of stalbe evaporation in capillary bundle was presented and experimental system of evaporation in capillary bundle was developed. By this system, stale evaporation of water in pipes was achieved. The arcjet with annular cavity covered anode was designed. By the annular cavity, the instability of vapor flowrate can be further decreased.Performance research on new designed arcjet was carried out when Argon was used as propellant. The specific impulse and efficiency of the new designed arcjet were compared to the same of the original one. The thrust of the new arcjet is improved from the original 100-135 s to 148-166 s, efficiency is improved from the original 21%-32% to 32%-53%.The results of the experiment prove that regenerative cooling method can improve the efficiency of low power arcjet remarkably.Performance research was carried out when water was propellant. The...