Influence of the Asymmetric Geometry of Inflow Ducts on the Performance of Nonequilibrium Disk-Shaped Magnetohydrodynamic Generators

Abstract

To examine the influence of the asymmetric geometry of inflow ducts on the performance of nonequilibrium disk-shaped magnetohydrodynamic (MHD) generators, we conducted MHD numerical simulations of a nonequilibrium disk-shaped MHD generator with an asymmetric, one-sided inflow duct and that with a symmetric, two-sided inflow duct. In our design concept, the two MHD generators have the same thermal input, applied magnetic field, and channel shape of the power extraction part. Numerical results show that the MHD generator with the one-sided inflow duct induces asymmetric distributions of plasma-fluid properties around the bent channel to connect the inflow duct with the channel of the MHD generator. However, the asymmetric distributions progressively disappear and transit to almost symmetric distributions before the plasma enters the power extraction part. Furthermore, the distributions of plasma-fluid properties in the power extraction part are almost identical to those in the MHD generator with the two-sided inflow duct. Consequently, the MHD generator with the one-sided inflow duct can obtain the same enthalpy extraction ratio (E.E.R.) as that with the two-sided inflow duct. Moreover, the numerical results indicate that the one-sided inflow duct is better for realizing high isentropic efficiency (I.E.) under the design concept used here than the two-sided inflow duct.