High-enthalpy extraction experiments with disk MHD generators

Power generation experiments have been performed for disk MHD generators with different channel shapes. The increase in the enthalpy extraction ratio by enlargement of the area ratio has been shown experimentally, and the highest enthalpy extraction ratio of 18.0% was achieved. The experimental results have shown that for the generator with the large area ratio, the wall static pressure in the MHD channel is kept lower than that for the small-area-ratio generator. These phenomena suggest that a high Hall parameter is obtained by enlargement of the area ratio. Furthermore, the swirl ratio at the channel exit was measured and was characterized by the ratio between Hall current and mass flow rate of the working gas.