HIGH-ENTHALPY EXTRACTION DEMONSTRATION WITH CLOSED-CYCLE DISK MHD GENERATORS

Recent results of high-enthalpy extraction experiments with closed-cyc le MHD disk generators are described. Power generation experiments wer e carried out with two types of facility: the shock tube facility with the Disk-IV generator and the FUJI-1 blow-down facility. In the shock tube experiments, the effect of channel shape on generator performanc e was studied using helium seeded with cesium as working fluid A more divergent channel shape was effective in sustaining a high Hall field throughout the channel and achieving high generator performance even u nder the strong MHD interaction. High-enthalpy extraction of 27.3 perc ent was achieved. Furthermore, these experimental results agree well w ith the results of one-dimensional calculations. In the FUJI-1 blow-do wn experiments, the effect of stagnation gas pressure on performance w as studied with a working gas of seeded argon. The highest enthalpy ex traction ratio of 15.7 percent was achieved with the lower stagnation pressure of 0.46 MPa, whereas the largest output power of 516.7 kW and power density of 70 MW/m(3) were extracted with the nominal stagnatio n pressure of 0.6 MPa. This suggested the possibility of a part-load o peration without significant degradation of generator performance by r educing stagnation pressure.