Experiments and numerical simulations in low power arcjets

This paper describes experimental setup and performance evaluation of laboratory model of low power arcjet thrusters. Radiation-cooled arcjet thrusters were operated in electric power below IkW with nitrogen and argon as propellant respectively, using a nozzle with 0.5~1.Omm in constrictor diameter and propellant mass flow rates varying from 20mg/sec to 40 mg/sec. Corresponding test parameters were measured including thrust, arc current, arc voltage, propellant mass flow rate, inlet pressure. Actual specific impulse, thrust efficiency and ratio of thrust and power were calculated. Parallel to the experiments a numerical code system was developed to compare with experimental data and further optimize the arcjet thruster. The numerical method is referred as a Non-Oscillatory and Non-free-Parameters Dissipative finite difference scheme (NND). Twodimension, axisymmetric, compressible channel flow N-S equation coupled with electromagnetism equation was solved. Experiments and calculations showed the agreement that operating performances using N₂ as propellant got much better than that of Ar, and presented that thruster with different structure and size had an optimal propellant mass flow rate with the best operating state.