Fundamental Experiment and Numerical Simulation of Ne/Xe Plasma Magnetohydrodynamic Electrical Power Generation

We conducted experiments in a shock-tube facility to test magnetohydrodynamic (MHD) electrical power generation with Xe-seeded Ne plasma. The performance and plasma behavior of the experimental generator were examined using time-dependent r-theta two-dimensional numerical simulations. In the experiment, an enthalpy extraction ratio of about 5.0% was obtained using a disk-shaped MHD generator with radio frequency pre-ionization. The numerical simulations show that the enthalpy extraction ratio is improved by adding small amounts of Xe to Ne, but also that adding excessive amounts of Xe deteriorates the generator performance. When an appropriate inlet electron temperature is assumed in the simulations, 5900-6450 K (inlet ionization degree of 0.25x10-4-0.72x10-4) for a seed fraction (mole % of Xe) of 0.1%, 6050-6280 K (1.08x10-4-1.70x10-4) for a seed fraction of 1.0%, and 5750-5950 K (1.27x10-4-1.97x10-4) for a seed fraction of 5.0%, the plasma structure almost becomes similar to the nonuniform plasma structure observed in the experiment, as too does the enthalpy extraction ratio. The simulations suggest that achieving an inlet ionization degree above 5-6x10-4 when using Ne/Xe with a seed fraction of 0.1-1.0% as the working gas should enable an enthalpy extraction ratio above 20%, which is expected to surpass that for pure Ar.