Performance of a 500-Kj Mhd Wind Tunnel

摘要

The operation of a pulsed MHD accelerator is described for a MHD wind tunnel application. The accelerator is designed to provide a 150% velocity increase (from 15,500 ft/sec to 24,000 ft/sec), at constant enthalpy, of a gas at approximately atmospheric pressure. The accelerator gas source is a hot shot that heats potassium seeded nitrogen to 9000K and 1400 atm. The gas is expanded into a segmented electrode (94 pair) MHD accelerator channel. After tunnel start-up, a 3-msec constant power pulse is switched on the electrodes so that current flow is approximately perpendicular to a quasi-steady 4-Wb/sq m magnetic field. The power-on to power-off velocity ratio at the accelerator exit is determined from changes in the stagnation pressure and open circuit induced potential. (Author)