Discharge Structure and Performance in Disk CCMHD Generator with Water Vapor

Abstract

The influence of water vapor contained in working gas on the discharge structure and performance in a closed cycle disk MHD generator is examined numerically. A model of the energy loss process due to inelastic collisions of electrons with water molecules is proposed. The contamination of water vapor is found to narrow the stable region in electron temperature where the fully ionized seed plasma is realized. It is confirmed from γ-θ two dimensional numerical simulations with the present model that water vapor contamination causes the strong nonuniform plasma and reduces the generator performance.