Thrust Measurement of KIII MPD Arcjet

AEROSPACE TECHNOLOGY JAPAN

et al. 2014

For a 500-to-900-kW-class steady-state self-field magnetoplasmadynamic (MPD) thruster, the thermal design is conducted with a combination of magnetohydrodynamic (MHD) and thermal analyses, where a heat flux evaluated from the MHD analysis is imposed on the electrode as a boundary condition in the thermal analysis. The increase in anode-to-cathode radius ratio improves the thrust performance, but can simultaneously raise the temperature locally at the anode exit edge and the cathode tip due to the concentration of the discharge current and/or the insufficient heat removal. It is suggested, however, that a thruster without electrode melting should be realizable even at such a high input power by setting an appropriate cathode radius and enhancing heat removal from the electrodes by means of heat pipe, although the achievable performance of the thruster depends on the assumption of the temperature of cathode root.

Section: Electrode Phenomenamentioning

confidence: 99%

Section: Electrode Phenomenamentioning

confidence: 99%

MHD Simulation and Thermal Design of an MPD Thruster

Kawasaki

Kubota

AEROSPACE TECHNOLOGY JAPAN

et al. 2014

“…Since the sheath effect is not included in the present model, we assume V sh to obtain the thrust efficiency. Although there are not comprehensive understandings on the sheath voltage drop in an MPD thruster, the sum of an anode sheath drop and a cathode sheath drop is supposed to range from 20 to 40 V [32]. In Fig.…”

Section: Thrust Efficiencymentioning

confidence: 99%

Comparison of Simulated Plasma Flow Field in a Two-Dimensional Magnetoplasmadynamic Thruster With Experimental Data

Kubota

IEEE Trans. Plasma Sci.

Okuno

2009

Comprehensive comparisons of the numerically simulated results of the plasma flowfields in a 100 kW class two-dimensional magnetoplasmadynamic thruster with available experimental data are conducted. The propellant is argon of 1.25 g/s and the discharge current is varied from 8 to 12 kA. The physical model includes non-equilibrium single-level of ionization and a collisional-radiative model for argon ion to assess the reaction processes in detail. The data we mainly compared are the current path, the electron number density and the electron temperature. There is qualitative agreement between the calculated and experimental results except for the electron temperature. In order to explain the disagreement of the electron temperature, we estimate the excitation temperature from the distributions of the excited ions in 4s and 4p states, radiation of which was employed to determine the electron temperature in the experiment. As a result, it is found that the calculated excitation temperature becomes close to the measured result, and that the plasma deviates from partial local thermodynamic equilibrium near the anode surface. Regarding the thrust and the thrust efficiency, their features against variation of the discharge current are well captured by the simulation, although they are slightly overestimated compared with measured values.

“…For example, utilization of the external magnetic field [5] or alternation of the propellant injection patterns [6] was often attempted. But the most fundamental way is to simply change the electrode configuration.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study for Electrode Configuration Problem in an MPD Thruster

Nakata

Toki

57th International Astronautical Congress

et al. 2006

It is well known that the performance of a MPD (MagnetoPlasmaDynamic) thruster is very affected by its geometries. Recently, some researcher pointed out the existence of "optimum electrode geometry" in their 1-dimensional computational studies. Optimum geometry had a few interesting feature, commonly based on converging-diverging geometry. But that has not been confirmed experimentally yet. We investigated the effects of each geometric parameter, using 6 type electrode configurations. Straight, 2 types of Flared and 3 types of converging-diverging anodes were tested at self-field, quasi-steady condition. The result was contrary to the foregoing expectation; the thruster performance was found to be almost indifferent to the change of the each parameter in the case of argon propellant.Nomenclature J = discharge current, kA V = discharge voltage, V T = thrust, N P= input power, kW