| NONEQUILIBRIUM ELECTRIC CONDUCTIVITY OF WET AND DRY POTASSIUM VAPOR, (2005) | |||||||||
Abstract | |||||||||
| The nonequilibrium electric conductivity of two-phase potassium vapor was studied both theoretically and experimentally. This study is important in connection with the design of Rankine-cycle alkali-metal magnetohydrodynamic (MHD) generators. The theoretical work indicates that small condensation droplets (mean radius less than 50 A) will detrimentally affect the achievement of elevated electron temperatures by Joule heating, and will also reduce the vapor ionization associated with this temperature. These effects, which arise from large electron-drop collision energy losses, are negligible when the mean droplet radius is greater than 200 A. A high-temperature (maximum temperature = 2000K) closed-loop facility was constructed for the study of nonequilibrium ionization in wet and dry potassium vapor. Preliminary experimental results on the electric conductivity of potassium in a subsonic test section are given. The results suggest that the condensation existed as a myriad of nucleation-sized (mean radius approx. 10 A) droplets which reduced the nonequilibrium conductivity appreciably below that of the dry vapor. (Author) | |||||||||
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