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Title: Surface interactions involved in flashover with high density electronegative gases.

Abstract

This report examines the interactions involved with flashover along a surface in high density electronegative gases. The focus is on fast ionization processes rather than the later time ionic drift or thermalization of the discharge. A kinetic simulation of the gas and surface is used to examine electron multiplication and includes gas collision, excitation and ionization, and attachment processes, gas photoionization and surface photoemission processes, as well as surface attachment. These rates are then used in a 1.5D fluid ionization wave (streamer) model to study streamer propagation with and without the surface in air and in SF6. The 1.5D model therefore includes rates for all these processes. To get a better estimate for the behavior of the radius we have studied radial expansion of the streamer in air and in SF6. The focus of the modeling is on voltage and field level changes (with and without a surface) rather than secondary effects, such as, velocities or changes in discharge path. An experiment has been set up to carry out measurements of threshold voltages, streamer velocities, and other discharge characteristics. This setup includes both electrical and photographic diagnostics (streak and framing cameras). We have observed little change in critical field levelsmore » (where avalanche multiplication sets in) in the gas alone versus with the surface. Comparisons between model calculations and experimental measurements are in agreement with this. We have examined streamer sustaining fields (field which maintains ionization wave propagation) in the gas and on the surface. Agreement of the gas levels with available literature is good and agreement between experiment and calculation is good also. Model calculations do not indicate much difference between the gas alone versus the surface levels. Experiments have identified differences in velocity between streamers on the surface and in the gas alone (the surface values being larger).« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Sandia National Laboratories
Sponsoring Org.:
USDOE
OSTI Identifier:
973670
Report Number(s):
SAND2010-0268
TRN: US201007%%188
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; GASES; ELECTRONEGATIVITY; FLASHOVER; INTERACTIONS; SURFACES; IONIZATION; KINETICS; EXCITATION; PHOTOEMISSION; PHOTOIONIZATION; COMPUTERIZED SIMULATION; TOWNSEND DISCHARGE; WAVE PROPAGATION; SULFUR FLUORIDES; Gas ionization.; Ionization of gases.; Wave propagation-Calculations.

Citation Formats

Hodge, Keith Conquest, Warne, Larry Kevin, Jorgenson, Roy Eberhardt, Wallace, Zachariah Red, and Lehr, Jane Marie. Surface interactions involved in flashover with high density electronegative gases.. United States: N. p., 2010. Web. doi:10.2172/973670.
Hodge, Keith Conquest, Warne, Larry Kevin, Jorgenson, Roy Eberhardt, Wallace, Zachariah Red, & Lehr, Jane Marie. Surface interactions involved in flashover with high density electronegative gases.. United States. doi:10.2172/973670.
Hodge, Keith Conquest, Warne, Larry Kevin, Jorgenson, Roy Eberhardt, Wallace, Zachariah Red, and Lehr, Jane Marie. Fri . "Surface interactions involved in flashover with high density electronegative gases.". United States. doi:10.2172/973670. https://www.osti.gov/servlets/purl/973670.
@article{osti_973670,
title = {Surface interactions involved in flashover with high density electronegative gases.},
author = {Hodge, Keith Conquest and Warne, Larry Kevin and Jorgenson, Roy Eberhardt and Wallace, Zachariah Red and Lehr, Jane Marie},
abstractNote = {This report examines the interactions involved with flashover along a surface in high density electronegative gases. The focus is on fast ionization processes rather than the later time ionic drift or thermalization of the discharge. A kinetic simulation of the gas and surface is used to examine electron multiplication and includes gas collision, excitation and ionization, and attachment processes, gas photoionization and surface photoemission processes, as well as surface attachment. These rates are then used in a 1.5D fluid ionization wave (streamer) model to study streamer propagation with and without the surface in air and in SF6. The 1.5D model therefore includes rates for all these processes. To get a better estimate for the behavior of the radius we have studied radial expansion of the streamer in air and in SF6. The focus of the modeling is on voltage and field level changes (with and without a surface) rather than secondary effects, such as, velocities or changes in discharge path. An experiment has been set up to carry out measurements of threshold voltages, streamer velocities, and other discharge characteristics. This setup includes both electrical and photographic diagnostics (streak and framing cameras). We have observed little change in critical field levels (where avalanche multiplication sets in) in the gas alone versus with the surface. Comparisons between model calculations and experimental measurements are in agreement with this. We have examined streamer sustaining fields (field which maintains ionization wave propagation) in the gas and on the surface. Agreement of the gas levels with available literature is good and agreement between experiment and calculation is good also. Model calculations do not indicate much difference between the gas alone versus the surface levels. Experiments have identified differences in velocity between streamers on the surface and in the gas alone (the surface values being larger).},
doi = {10.2172/973670},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2010},
month = {1}
}

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