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Title: Effects of viscosity in a partially ionized channel flow with thermionic emission

Abstract

The flow of the partially ionized gas inside thermionic hollow cathodes spans a diverse range of theoretical disciplines in plasma physics and fluid mechanics. Understanding and predicting the evolution of such flows has many practical implications because hollow cathodes are critical components of electric propulsion systems used onboard scientific and commercial spacecraft presently in space or in the mission planning stages. As space missions become more demanding of the propulsion system in terms of throughput, understanding and predicting failure mechanisms of the system becomes imperative. Two-dimensional numerical simulations of the partially ionized gas generated by a thermionic hollow cathode have been performed to quantify the effects of viscosity inside the cylindrical channel of the device. A comparison of the inviscid and fully viscous flow fields shows that viscosity has a significant impact on the atomic species and a lesser effect on the ions. The internal pressure is determined to be more than 40% higher compared to the inviscid solution and the Reynolds number for the flow of atoms is found to be less than 20 inside the channel. Although the Mach number is computed to be <0.1 for approximately 95% of the channel, the solution for the velocity flow fieldmore » begins to deviate from the Poiseuille (parabolic) solution at about 50% of the channel due mainly to collisional drag with ions.« less

Authors:
 [1]
  1. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)
Publication Date:
OSTI Identifier:
21272475
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 16; Journal Issue: 1; Other Information: DOI: 10.1063/1.3056397; (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; HOLLOW CATHODES; PLASMA; PLASMA SIMULATION; PROPULSION SYSTEMS; THERMIONIC EMISSION; TWO-DIMENSIONAL CALCULATIONS; VISCOSITY; VISCOUS FLOW

Citation Formats

Mikellides, Ioannis G. Effects of viscosity in a partially ionized channel flow with thermionic emission. United States: N. p., 2009. Web. doi:10.1063/1.3056397.
Mikellides, Ioannis G. Effects of viscosity in a partially ionized channel flow with thermionic emission. United States. https://doi.org/10.1063/1.3056397
Mikellides, Ioannis G. 2009. "Effects of viscosity in a partially ionized channel flow with thermionic emission". United States. https://doi.org/10.1063/1.3056397.
@article{osti_21272475,
title = {Effects of viscosity in a partially ionized channel flow with thermionic emission},
author = {Mikellides, Ioannis G},
abstractNote = {The flow of the partially ionized gas inside thermionic hollow cathodes spans a diverse range of theoretical disciplines in plasma physics and fluid mechanics. Understanding and predicting the evolution of such flows has many practical implications because hollow cathodes are critical components of electric propulsion systems used onboard scientific and commercial spacecraft presently in space or in the mission planning stages. As space missions become more demanding of the propulsion system in terms of throughput, understanding and predicting failure mechanisms of the system becomes imperative. Two-dimensional numerical simulations of the partially ionized gas generated by a thermionic hollow cathode have been performed to quantify the effects of viscosity inside the cylindrical channel of the device. A comparison of the inviscid and fully viscous flow fields shows that viscosity has a significant impact on the atomic species and a lesser effect on the ions. The internal pressure is determined to be more than 40% higher compared to the inviscid solution and the Reynolds number for the flow of atoms is found to be less than 20 inside the channel. Although the Mach number is computed to be <0.1 for approximately 95% of the channel, the solution for the velocity flow field begins to deviate from the Poiseuille (parabolic) solution at about 50% of the channel due mainly to collisional drag with ions.},
doi = {10.1063/1.3056397},
url = {https://www.osti.gov/biblio/21272475}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 1,
volume = 16,
place = {United States},
year = {Thu Jan 15 00:00:00 EST 2009},
month = {Thu Jan 15 00:00:00 EST 2009}
}