Numerical Study on Performance of a Xenon-Seeded Neon Plasma Magnetohydrodynamic Electrical Power Generator

The performance of a disk-shaped magnetohydrodynamic (MHD) electrical power generator with a neon (Ne)/xenon (Xe) working gas is examined by r–z and r– $ {\theta }$ 2-D numerical simulations. The results obtained from these simulations are compared in order to evaluate the generator performance precisely, including the effects of the boundary layer and plasma uniformity. Both the r–z and r– $ {\theta }$ simulations show that adding small amounts of Xe can reduce the pre-ionization power ratio (P.P.R.) without changing the generator performance, whereas adding an excessive amount deteriorates the performance. Under the optimum conditions, the plasma structure obtained in the r– $ {\theta }$ simulation becomes uniform, and the plasma and fluid flow properties are almost the same as those obtained in the r–z simulation. At that time, the enthalpy extraction ratio (E.E.R.) and isentropic efficiency (I.E.) obtained from these simulations are almost similar. Generator performance is slightly lower in the r–z numerical simulation than in the r– $ {\theta }$ simulation because of the velocity decrease in the boundary layer near the walls. In the r– $ {\theta }$ simulation, when a nonuniform plasma appears, the generator performance deteriorates drastically and becomes much lower than that in the r–z simulation.