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Electrode Conduction Processes Segmented Electrode-Insulator Ratio Effects in MHD Power Generation Experiments

Conference:

Abstract

(a) Electrode conduction processes have been investigated using a plasma produced in an electromagnetic shock tube operating with argon at 70 {mu}mHg pressure. Complete voltage-current characteristics were obtained by the variation of load and applied voltage. These indicated the existence of two conduction regimes with a complex transition region. In the first regime the current, controlled by ion mobility, rose linearly with voltage to saturate between 10 mA and 1 A depending on conditions. Electrode contamination was significant. The second regime involved large currents controlled by electron mobility and emission from the cathode. The current again increased linearly with voltage and reached 200 A. Observation of induced voltages in transverse magnetic fields and of plasma deceleration in non-uniform fields showed that in the electromagnetic shock tube the plasma was heated predominantly by the driver discharge. Its conductivity was calculated using properties measured by a Langmuir double probe. In both regimes the plasma conductivity was also found from the gradient of the voltage current characteristics using experimental electric field fringing factors and the experimental values were compared with theory. (b) Larger-scale experiments used a combustion-driven shock tube where argon plasma flow, magnetic field and induced current flow were mutually orthogonal. The  More>>
Authors:
Pain, H. J.; Fearn, D. G.; Distefano, E. [1] 
  1. Imperial College. London (United Kingdom)
Publication Date:
Oct 15, 1966
Product Type:
Conference
Report Number:
IAEA-SM-74/8
Resource Relation:
Conference: Symposium on Magnetohydrodynamic Electrical Power Generation, Salzburg (Austria), 4-8 Jul 1966; Other Information: 19 refs., 10 figs.; Related Information: In: Electricity from MHD. Vol. I. Proceedings of a Symposium on Magnetohydrodynamic Electrical Power Generation| 728 p.
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ARGON; CATHODES; COMBUSTION; COMPARATIVE EVALUATIONS; ELECTRIC POTENTIAL; ELECTRON MOBILITY; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; MHD GENERATORS; PLASMA; POWER GENERATION; SHOCK TUBES; SUPERSONIC FLOW
OSTI ID:
22113804
Research Organizations:
International Atomic Energy Agency, Vienna (Austria); European Nuclear Energy Agency of the OECD, Issy-les-Moulineaux (France)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13M1690070786
Submitting Site:
INIS
Size:
page(s) 161-173
Announcement Date:
Jul 20, 2013

Conference:

Citation Formats

Pain, H. J., Fearn, D. G., and Distefano, E. Electrode Conduction Processes Segmented Electrode-Insulator Ratio Effects in MHD Power Generation Experiments. IAEA: N. p., 1966. Web.
Pain, H. J., Fearn, D. G., & Distefano, E. Electrode Conduction Processes Segmented Electrode-Insulator Ratio Effects in MHD Power Generation Experiments. IAEA.
Pain, H. J., Fearn, D. G., and Distefano, E. 1966. "Electrode Conduction Processes Segmented Electrode-Insulator Ratio Effects in MHD Power Generation Experiments." IAEA.
@misc{etde_22113804,
title = {Electrode Conduction Processes Segmented Electrode-Insulator Ratio Effects in MHD Power Generation Experiments}
author = {Pain, H. J., Fearn, D. G., and Distefano, E.}
abstractNote = {(a) Electrode conduction processes have been investigated using a plasma produced in an electromagnetic shock tube operating with argon at 70 {mu}mHg pressure. Complete voltage-current characteristics were obtained by the variation of load and applied voltage. These indicated the existence of two conduction regimes with a complex transition region. In the first regime the current, controlled by ion mobility, rose linearly with voltage to saturate between 10 mA and 1 A depending on conditions. Electrode contamination was significant. The second regime involved large currents controlled by electron mobility and emission from the cathode. The current again increased linearly with voltage and reached 200 A. Observation of induced voltages in transverse magnetic fields and of plasma deceleration in non-uniform fields showed that in the electromagnetic shock tube the plasma was heated predominantly by the driver discharge. Its conductivity was calculated using properties measured by a Langmuir double probe. In both regimes the plasma conductivity was also found from the gradient of the voltage current characteristics using experimental electric field fringing factors and the experimental values were compared with theory. (b) Larger-scale experiments used a combustion-driven shock tube where argon plasma flow, magnetic field and induced current flow were mutually orthogonal. The supersonic flow velocity and thermodynamic parameters of the plasma were accurately known. The electrode channel consisted of a segmented system of 12 electrode pairs with an electrode insulator ratio ranging from 1 to 21, with electrode plus insulator length remaining constant, and with maximum Hall parameter values of unity. Different electrode load combinations (Faraday and Hall generators) have been studied in measuring the power generated and the flow of longitudinal currents between adjacent electrodes. A maximum power of 0,8 MW was obtained, the power output decreasing inversely with the electrode insulator ratio. The results are compared with existing theory. (author)}
place = {IAEA}
year = {1966}
month = {Oct}
}