Cathode erosion studies on MPD thrusters

Schrade, H. O.; Auweter‐Kurtz, Monika; Kurtz, H.

doi:10.2514/3.9750

Cited by 35 publications

(13 citation statements)

References 10 publications

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“…4 Fig. 6 Rectifier characteristics currents and, thus, higher enthalpies [47]. Oxygen injection downstream of the throat protects the hot cathode from oxidation.…”

Section: Pwk1mentioning

confidence: 99%

Assessment of high enthalpy flow conditions for re-entry aerothermodynamics in the plasma wind tunnel facilities at IRS

Loehle¹,

Zander

Eberhart³

et al. 2021

CEAS Space J

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This article presents the full operational experimental capabilities of the plasma wind tunnel facilities at the Institute of Space Systems at the University of Stuttgart. The simulation of the aerothermodynamic environment experienced by vehicles entering the atmosphere of Earth is attempted using three different facilities. Utilizing the three different facilities, the recent improvements enable a unique range of flow conditions in relation to other known facilities. Recent performance optimisations are highlighted in this article. Based on the experimental conditions demonstrated a corresponding flight scenario is derived using a ground-to-flight extrapolation approach based on local mass-specific enthalpy, total pressure and boundary layer edge velocity gradient. This shows that the three facilities cover the challenging parts of the aerothermodynamics along the entry trajectory from Low Earth Orbit. Furthermore, the more challenging conditions arising during interplanetary return at altitudes above 70 km are as well covered.

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“…4 Fig. 6 Rectifier characteristics currents and, thus, higher enthalpies [47]. Oxygen injection downstream of the throat protects the hot cathode from oxidation.…”

Section: Pwk1mentioning

confidence: 99%

Assessment of high enthalpy flow conditions for re-entry aerothermodynamics in the plasma wind tunnel facilities at IRS

Loehle¹,

Zander

Eberhart³

et al. 2021

CEAS Space J

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show abstract

“…Moreover, in depth study has done on the temperature effect on the cathode. The high erosive extraction is typical of cold cathode operation, while thermionic current emission occurs in heated-cathode operation that substantially lowers the rate of erosion of electrode [24]. However, the major benefit of cathode heating is the substantial drop in the erosion rate, which indicates directly lengthening thruster life [25].…”

Section: Thermo-ionic Emission From Cathodementioning

confidence: 99%

MPD Thruster Technology and Its Limitations

Patel¹,

Bondugula²,

Gorakula³

2021

International Journal of Scientific Advances

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It was realized earlier that chemical propulsion systems utilize fuel very inefficiently, which greatly limits their lifespan. Electric propulsion is into existence to overcome this limitation of chemical propulsion. The magnetoplasmadynamic (MPD) thruster is presently the most powerful form of electromagnetic propulsion. It is the thruster’s ability to efficiently convert MW of electric power into thrust which gives this technology a potential to perform several orbital as well as deep space missions. MPD thruster offers distinct advantages over conventional types of propulsion for several mission applications with its high specific impulse and exhaust velocities. However, MPD thruster has limitations which limits its operational efficiency and lifetime. In this paper, the thruster limitations are reviewed with respect to three operational limits i.e., the onset phenomenon, cathode lifetime, and thruster overfed limits. The dependence and effects of the operational limits on each other is compared using different empirical models to derive a scaling factor that has been found for each geometrical arrangement; a limiting value exists beyond which the operation becomes highly unsteady and electrode erosion occurs. Along with reviewing and proposing methods to overcome power limitations for MPD thrusters, the relation between exit velocity and ratio of electrode’s radius is also verified using Maecker’s formula.

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“…The cathode erosion mechanism varies with different devices and also with different stages in the operation of a given device: these can be divided into a start-up stage and a steady-state stage [10]. During the start-up stage, there are quantities of tiny spots on the cathode surface, the current density of which can reach 10 12 A m −2 [11]. Due to this high current density, local corrosion and sputtering are the main cause of the erosion.…”

Section: Introductionmentioning

confidence: 99%

Cathode erosion site distributions in an applied-field magnetoplasmadynamic thruster

Wang

Li³

et al. 2020

Plasma Sci. Technol.

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Erosion can influence cathode life, and is thus considered to be one of the main factors limiting the application of applied-field magnetoplasmadynamic thrusters. In this paper, erosion sites on graphite cathodes are studied so as to identify the influence of applied magnetic field and the ratio of propellant mass flow rate supplied from cathode and anode. The experiment results show that the application of applied magnetic field can significantly reduce the erosion rate of the cathode compared to that without magnetic field. The erosion sites on the cathode vary with the relative position of the convergent-divergent magnetic field, and are mainly distributed in the divergent part of the field. The erosion sites on the cathodes are found to be related to the propellant supply. The decreasing anode mass flow rate enlarges the range of erosion. These results are much helpful for the analysis of cathode erosion site location since they provide evidences of erosion mechanisms and point out the directions for further research.

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Cathode erosion studies on MPD thrusters

Cited by 35 publications

References 10 publications

Assessment of high enthalpy flow conditions for re-entry aerothermodynamics in the plasma wind tunnel facilities at IRS

Assessment of high enthalpy flow conditions for re-entry aerothermodynamics in the plasma wind tunnel facilities at IRS

MPD Thruster Technology and Its Limitations

Cathode erosion site distributions in an applied-field magnetoplasmadynamic thruster

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