高温ガスの熱力学・輸送特性に基づく残留アークコンダクタンスの低下過程の解明

概要

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The decaying aspect of the conductance of an arc after a current zero for SF6, N2, O2, air, c-C4F8, CO2, H2, He and Ar was studied on the basis of thermodynamic and transport properties of high temperature gases: a mass density ρ, an enthalpy h, an enthalpy h300 at 300 K, a specific heat CP, and a thermal conductivity κ and an electrical conductivity σ. Theoretical calculation revealed two principal phenomena as follows:(1) for the case in presence of gas flow, the conductances for SF6, c-C4 F8, O2, CO2, H2, He and Ar decay rapidly just around a current zero and (2) the conductances for H2 and He in no axial gas-flow decrease in an almost similar aspect to that for the case in presence of the gas flow. To explain the phenomenon (2), a thermal diffusivity α expressed as α = κ /(ρ CP) was calculated. The H2 and He proved to have very much higher α than the others. This higher α of the H2 and He was found to result in the more rapid reduction in the conductance through a thermal conduction mechanism. To interpret the phenomenon (1), β expressed as β =(h-h300)/(ρCP) was calculated. The SF6, c-C4 F8, O2, CO2 and Ar were found to have higher β than N2 and air. This higher β of SF6, c-C4F8, O2, CO2 and Ar proved to cause the more rapid diminution in the conductance through convection mechanism.
社団法人電気学会の論文
2003-04-01