Abstract
Structures of plasma and fluid flow in a nonequilibrium disk MHD generator driven with lOOMWth He-Cs working gas are examined with three dimensional numerical simulations. It is confirmed that the boundary layer is relatively thin and the main flow part remains under the condition of high enthalpy extraction with a uniform and steady plasma. For a low load resistance, nonuniform and unsteady streamer structure appears in the γ-φ plane due to the ionization instability caused by the partial ionization of seed atoms, and the structure holds in the height (z) direction for a large generator channel. It is clearly shown for a high load resistance that the boundary layer becomes considerably thick and separates, and the strong MHD interaction makes the structure like pseudo-shock waves, particulary in the upstream region of the generator. The structure of fluid flow is circular in the upstream region, while the flow is affected by the nonuniform and unsteady domain structure attributed to noble gas ionization in the downstream region.
