CLOSED CYCLE MHD POWER GENERATION EXPERIMENTS USING A HELIUM-CESIUM WORKING FLUID IN THE NASA LEWIS FACILITY

摘要

Since the last EAM Symposium, the MHD channel, which was previously operated for over 500 hours of thermal operation, ten thermal cycles, and 200 cesium injection tests, was removed from the facil¬ity and redesigned. The cross sectional dimensions of the channel were reduced to 5 by 16.5 cm to allow operation over a variety of conditions. The redesigned channel has been operated for well over 300 hours, 10 thermal cycles, and 150 cesium injec¬tion tests with no problems. Experiments have been g run at temperatures of 1900-2100 K and Mach numbers g from 0.3 to 0.55 in argon and 0.2 in helium. The ability to run over a variety of conditions coupled with improvements in Hall voltage isolation and seed vaporization techniques have increased our understanding of the generator phenomena and have resulted in significant improvements in performance. The best results to date have been obtained in the helium tests. Typical values obtained with helium are Faraday open circuit voltage VFOC = 141 V (92% of uBh) at B = 1.7 T, power outputs of 2.2kw for tests with 28 electrodes and 2.1kw for tests with 17 electrodes. Power densities of 0.6 MW/m3 and Hall fields of ~llOO V/m were obtained in the tests with 17 electrodes. These results represent a factor of VL8 improvement in power density over the previously reported results. However, the V-l curves and current distribution data indicate that while near ideal equilibrium performance is ob¬tained under some conditions, no non-equilibrium power has been generated to date.