Study of A disk MHD generator for nonequilibrium plasma generator (NPG) system

Design and performance prediction studies of a disk type magnetohydrodynamic (MHD) generator which is applied to the non- equilibrium plasma generator (NPG) system have been carried out. The main objective of the present study is to know whether sufficiently high output performance demonstration can be possible with the disk generator which is planned to be used for NPG-MHD disk pulse power demonstration. Present numerical simulation showed that the original constant height channel could provide not more than 20% of enthalpy extraction because its channel shape could not sustain working plasma in the stable regime against ionization instability throughout the channel. We concluded that in order to obtain much higher generator performance, detailed design of channel shape was necessary. Design work has also been carried out based upon the concept that local electron temperature must be kept at 5000K, i.e. the plasma must be controlled to locate at the center of stable regime. With the designed channel, enthalpy extraction of up to 40% and output power of 7.2MW can be successfully expected under the thermal input of 18MW. In addition, the designed channel requires no major modification of the supersonic nozzle, the inlet swirl vanes and the configuration of magnet system.