Plasma and cathode emission from a high power hydrogen arcjet

Berns, Darren; Storm, P.; Hargus, William A.; Cappelli, Mark A.; McFall, Keith A.; Spores, Ronald A.

doi:10.2514/6.1996-2703

Cited by 2 publications

(3 citation statements)

References 9 publications

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“…Such misalignment of the cathode tip and constrictor has been observed during experiments on arcjet thrusters [18,19], which resulted in a shifted arc column. This resulted in asymmetric current density distribution and asymmetric heating.…”

Section: Introductionmentioning

confidence: 56%

“…Arcjet performance is strongly influenced by the processes near the cathode tip and the constrictor region. Therefore, as observed in the experiments of Glocker et al [19], an unsymmetrical arc could affect thruster performance and produce a side thrust. While it is desirable to perform simulations over various cathode offset distances, due to the exorbitant computational cost and excessive time for such a study, it is not undertaken here.…”

Section: Influence Of Cathode Tip Offset From Thruster Axismentioning

confidence: 85%

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A three-dimensional numerical study on the effect of geometric asymmetry on arcjet thruster performance

Nandyala

Kumar

Jayachandran

2023

Plasma Sci. Technol.

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In an arcjet thruster, the cathode and constrictor degrade with time, and the electrical arc discharge may become unsymmetrical. In this work, a three-dimensional numerical model of hydrogen plasma arcjet is developed and validated to study the effect of unsymmetrical electric arc discharge on thruster performance. The unsymmetrical arc discharge is realized by introducing a radial shift of the cathode so that the cathode tip offset is 80 μm (25 % of the constrictor radius). Simulations are conducted for both axially centered cathode (coaxial) and off-centered cathode (non-coaxial) configurations with identical propellant flow rates and input current. Simulations show asymmetrical arc discharge in non-coaxial cathode configuration, resulting in azimuthally asymmetric Joule heating, species concentrations, and velocity field. This asymmetry continues as the plasma expands in the divergent section of the nozzle. Temperature, species concentrations, and axial velocity exhibit asymmetric radial distribution at the nozzle exit. The computed Joule heating was found to reduce with cathode shift, and consequently, the thrust and specific impulse of the thruster was decreased by about 6.6 %. In the case of the non-coaxial cathode, geometric asymmetry also induces a small side thrust.

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Section: Introductionmentioning

confidence: 56%

Section: Influence Of Cathode Tip Offset From Thruster Axismentioning

confidence: 85%

A three-dimensional numerical study on the effect of geometric asymmetry on arcjet thruster performance

Nandyala

Kumar

Jayachandran

2023

Plasma Sci. Technol.

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“…The 0.16 mm crater corresponds to an attachment area of approximately ´-2 10 m . 8 2 Moreover, Bearns et al [44] found the current density profile at cathode tip constricted in size when the mass flow rate is increased for a constant current and expanded in size when current is increased for constant mass flow rate. In the experiments on vacuum discharge with a copper cathode for a fixed current, Daalder et al [41] found craters with diameters varying over a wide range.…”

Section: Sheath Modelmentioning

confidence: 99%

Numerical simulation of hydrogen arcjet thruster with coupled sheath model

Akhare¹,

Nandyala²,

Jayachandran³

et al. 2022

Plasma Sci. Technol.

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In the present work, a complete 2D chemical and thermal non-equilibrium numerical model coupled with a relatively simple sheath model is developed for hydrogen arcjet thruster. Conduction heat transfer in the anode wall is also included in the model. The operating voltages predicted by the model are compared with those in the literature and are found to be in close agreement. Power distributions for the various operating conditions are obtained, anode radiation loss primarily determines the thruster efficiency. Higher thruster efficiency was found to be associated with longer arc length. At cathode ion diffusion contribution dominates except at low input current where thermo-field electron current is dominant.

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Plasma and cathode emission from a high power hydrogen arcjet

Cited by 2 publications

References 9 publications

A three-dimensional numerical study on the effect of geometric asymmetry on arcjet thruster performance

A three-dimensional numerical study on the effect of geometric asymmetry on arcjet thruster performance

Numerical simulation of hydrogen arcjet thruster with coupled sheath model

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