r-z two-dimensional numerical simulations of a frozen inert gas plasma MHD generator

In a magnetohydrodynamics (MHD) power generation with a frozen inert gas plasma (FIP), the effect of the nonuniformity of the inlet plasma in the direction perpendicular to walls on the performance and the comparison of the performance with r-θ two-dimensional (2-D) numerical simulations are examined with r-z 2-D ones. The inlet nonuniformity of an ionization degree is kept throughout the channel and even in the boundary layer the state of the FIP is realized without an ionization instability. When the inlet ionization degree near the walls is higher than that in the main flow, the enthalpy extraction ratio decreases because the strong MHD interaction near the wall leads to the development of the boundary layer. On the other hand, it increases for the inverse distribution at the channel inlet, even if the introduced total inlet ionization degree is the same. In comparison with the results obtained from the r-θ simulation, the development of the boundary layer results in the deterioration of the performance, and the optimal condition shifts to the low inlet ionization degree and the high load resistance.