Since its invention at the University of Stuttgart, Germany in the mid-1960, scientists have been trying to understand and explain the mechanism of the plasma interaction inside the magnetoplasmadynamics (MPD) thruster. Because this thruster creates a larger level of efficiency than combustion thrusters, this MPD thruster is the primary cadidate thruster for a long duration (planetary) spacecraft. However, the complexity of this thruster make it difficult to fully understand the plasma interaction in an MPD thruster while operating the device. That is, there is a great deal of physics involved: the fluid dynamics, the electromagnetics, the plasma dynamics, and the thermodynamics. All of these physics must be included when an MPD thruster operates.
In recent years, a computer simulation helped scientists to simulate the experiments by programing the physics theories and comparing the simulation results with the experimental data. Many MPD thruster simulations have been conducted: E. Niewood et al., C. K. J. Hulston et al., K. D. Goodfellow, J Rossignol et al.. All of these MPD computer simulations helped the scientists to see how quickly the system responds to the new design parameters.
For this work, a 1D MPD thruster simulation was developed to find the voltage drop between the cathode and the plasma regions. Also, the properties such as thermal conductivity, electrical conductivity and heat capacity are temperature and pressure dependent. These two conductivity and heat capacity are usually definded as constant values in many other models. However, this 1D and 2D cylindrical symmetry MPD thruster simulations include both temperature and pressure effects to the electrical, thermal conductivities and heat capacity values interpolated from W. F. Ahtye . Eventhough, the pressure effect is also significant; however, in this study the pressure at 66 Pa was set as a baseline.
The 1D MPD thruster simulation includes the sheath region, which is the interface between the plasma and the cathode regions. This sheath model  has been fully combined in the 1D simulation. That is, the sheath model calculates the heat flux and the sheath voltage by giving the temperature and the current density. This sheath model must be included in the simulation, as the sheath region is treated differently from the main plasma region.
For our 2D cylindrical symmetry simulation, the dimensions of the cathode, the anode, the total current, the pressure, the type of gases, the work function can be changed in the input process as needed for particular interested. Also, the sheath model is still included and fully integrated in this 2D cylindrical symmetry simulation at the cathode surface grids. In addition, the focus of the 2D cylindrical symmetry simulation is to connect the properties on the plasma and the cathode regions on the cathode surface until the MPD thruster reach steady state and estimate the plasma arc attachement edge, electroarc edge, on the cathode surface. Finally, we can understand more about the behavior of an MPD thruster under many different conditions of 2D cylindrical symmetry MPD thruster simulations.
|Commitee:||Gruntman, Mike, Kunc, Joseph, Nakano, Aiichiro, Wang, Joseph|
|School:||University of Southern California|
|Department:||Aerospace Engineering (Astronautics)|
|School Location:||United States -- California|
|Source:||DAI-B 76/10(E), Dissertation Abstracts International|
|Keywords:||1d magnetoplasmadynamics thruster simulation, 2d cylindrical symmetry magnetoplasmadynamics thruster simulation, Electroarc edge, Magnetoplasmadynamics thrusters, Outline of algorithm of mpd thruster simulation, Plasma attach edge|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be