Geometric Parameter Effect of Magneto-Plasma-Dynamic thruster

Paper number

IAC-05-E2.P.11

Author

Mr. Daisuke Nakata, University of Tokyo, Japan

Year

2005

Abstract

The electric propulsion system enables us various space missions with much less propellant consumption as compared to chemical propulsion system. Until now, mainly ion engines and hall thrusters, which are based on the electrostatic acceleration mechanism, have been used for more than 100 satellites and come to be used for a few deep space probes. 
 In the near future, more powerful electric propulsion system must be essential to enable large-scale interplanetary missions. Not only the efficient propellant consumption but also the short trip time (by powerful engine) is also necessary to achieve the frequent interplanetary cruise.
 MPD(Magnetoplasmadynamic) Arcjet, which has both high thrust density and high specific impulse, is one of the most promising propulsion system to meet these demanding mission requirements. 
It is well known that the performance of the MPD thruster is strongly affected by its electrode nozzle configuration. But their relation is not cleared because the internal flow field condition depends on the complicated interaction of many physical factors involving internal arc current distribution, plasma instability and local temperature nonequilibrium. Resultantly, a variety of geometries are attempted in each organization in the world.
 In Japan, a study to seek the optimum geometry using numerical method is now progressing, and recently pointed out the following guideline. Typically, the arc current strongly concentrates on the cathode tip and cathode root. So, it is preferable to use the configuration whose electrode gap is shortened in the middle region of the discharge chamber to make uniform current distribution. Besides, the shape of the downstream region should be flared quickly. These remarks were based on the simple one-dimensional framework, so it has to be verified by actual experiment. We have carried out the validation of this remarks using 12 type electrodes. They have different throat diameter (12, 18, 24mm), outlet diameter (60, 80, 100mm) or cathode length (13mm or 42mm). From the detail experiment, it was turned out that there was the moderate scale parameters to achieve a smooth flow field for a fixed input power. Especially, we are going to focus on similar or different tendencies between the numerical simulation and experimental results.

Abstract document

IAC-05-E2.P.11.pdf

Manuscript document

IAC-05-E2.P.11.pdf (🔒 authorized access only).

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