SUMMARYAn experimental study on performance of a disk MHD generator was carried out using a shock-tube driven facility. Effects of nozzle load resistance and stagnation gas pressure on the enthalpy extraction, the total pressure ratio, and the adiabatic efficiency were investigated for a disk MHD generator with a small area ratio. The enthalpy extraction and the adiabatic efficiency were found to be affected by the nozzle load resistance. The results suggest that the nozzle load resistance should be kept high for high performance of the disk MHD generator with small area ratio. Furthermore, an increase of stagnation pressure resulted in a slight increase of enthalpy extraction. However, the increase of stagnation pressure led to a remarkable increase of adiabatic efficiency. The increase of the adiabatic efficiency was due to an increase of the total pressure ratio. The effects of the electrical efficiency, the Mach number, and loss parameters for heat and friction on the total pressure ratio are discussed. The discussion suggests that the increase of total pressure ratio is due to a relative decrease of pressure loss due to wall friction. In addition, the highest adiabatic efficiency for cesium-seeded argon was achieved in the present experiment without the introduction of inlet swirl. © 2001 Scripta Technica, Electr Eng Jpn, 137(3): 3746, 2001

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Heat flux measurements have been performed with calorimeter probes in closed poloidal-divenor reversed-field pinch (RFP) discharges in the STE-2. A high heat flux with large anisotropy has been observed at the edge of the main plasma, indicating the existence of the fast edge electrons in divenor RFP discharges. The spatial distribution measurements show that a fractiou of the fast edge electrons is also exhausted into the divertor chamber as fast (superthermal) electrons. It is also shown that most of the parallel heat flux in the divertor chamber is canied by the fast elect".

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