Closed cycle MHD blow-down experiments with helium working gas

Results of high enthalpy extraction experiments in the FUJI-1 closed cycle MUD blow-down facility driven by helium working gas were described. For the case of hcliunt, large loss of stagnation pressure along the flow direction was measured and the amount of pressure loss could be explained by the twice of larger friction loss than usual one. In the first series of power generation experiments, the output power regained small level compared to the case of argon because of the large voltage drop at the inlet of a disk channel. The effects of seed fraction and stagnation pressure on the performances were studied in the latest series of experiments. The results showed that the increase of seed fraction and of stagnation pressure was much effective to reduce the voltage drop and to improve the performances. Tine dependent electron temperature measurements were succeeded by the detection of recombination radiation. Measured electron temperature In the downstream part of channel was in the stable regime of full seed Ionization.