ENERGY EFFICIENCY TRENDS IN A COAXIAL GUN PLASMA ENGINE SYSTEM

摘要: The efficiency of converting capacitor stored energy into in the exhaust stream a repetitively pulsed two-stage coaxial plasma engine has been determined calorimetrically for various capacitances, voltages, gas densities and density profiles, gun geometries. Observed trends have led to empirically optimum lengths, electrode . radius ratios, storage voltages. Energy efficiencies 63% measured so far, without having reached leveling off increase trend. largest gains realized by new approach pulse injection, which provides more complete filling barrel with propellant axial rather than radial injection prior discharge. most efficient configuration resulting from calorimetric studies was placed on thrust balance along its associated system, data were obtained. Propellant mass flow rate also measured, results combined determine over-all (770 = T 2/2raP) specific impulses (/sp T/mg). efficiencies, typically significantly lower calorimetrically, since large fraction injected not utilized Adjustment r?o /sp, taking account unused mass, gave rise higher 770 but at undesirably high jTsp. Additional steps taken improve system performance are discussed.