Closed cycle MHD generator with nonuniform gas-plasma flow driving recombinated plasma clots

Abstract

A new concept of a closed-cycle MHD generator without alkali seed has been suggested. The essence of it is the phenomenon of frozen conductivity for recombinated plasma which appears for noble gases at T/sub e/>4000 K. At the inlet of the MHD channel in the supersonic flow of noble gas (He or Ar), plasma clots with an electron density of about 10/sup 15/ cm/sup -3/ are formed by a pulsed intense electron beam with an energy of about 300 keV. The gas flow drives these clots in a cross-magnetic field along the MHD channel which has electrodes connected to the load by a Faraday scheme. The gas flow pushes the plasma layers and produces electric power at the expense of enthalpy extraction. A numerical simulation has shown that a supersonic gas flow, containing about 4 plasma layers in the MHD channel simultaneously, is braked without shock wave creation. This type of MHD generator can provide more than a 30% enthalpy extraction ratio and about an 80% isentropic efficiency. The advantages of the new concept are: (a) the possibility of working at higher pressures and lower temperatures; and (b) operation without alkali seed.