Performances of disk CCMHD generator with small area ratio

Abstract

Performances of disk MHD generator with small area ratio were studied experimentally. The experiments were carried out using shock-tube facility, and cesium seeded argon was used as a working fluid. In the present experiments, two inlet stagnation gas pressure of 0.21MPa and 0.29MPa were selected. The highest adiabatic efficiency(=45.9%) was achieved at higher stagnation pressure. High enthalpy extraction of 17.2% remained obtained at the same time. At lower stagnation pressure, adiabatic efficiency remained lower(=39.7%) although almost the same enthalpy extraction of 17.3% was achieved. The difference in adiabatic efficiency between two stagnation pressures is due to the difference in stagnation pressure ratio between channel exit and inlet. It is considered that these differences are caused by differences in friction loss and/or electrical efficiency. Furthermore, a simple analysis suggests that positive swirl in the channel results in higher electrical efficiency. Therefore an introduction of inlet swirl will be useful for further improvement of disk MHD generator performances.