負荷変化によるディスク形MHD発電機の過渡現象

抄録

Results of experimental study on transient phenomena of the closed cycle disk MHD generator are described in this paper. The transient phenomena were caused by a step-like change of load resistance during a test time of the shock-tube driven disk MHD generator. The load resistance was changed by using an IGBT (Insulated Gate Bipolar Transistor) installed in a load circuit. When the load resistance was changed from 0.096Ω to 2.5Ω, an overshoot of the Hall output voltage and of the Hall electric field was observed, and a large fluctuation of static pressure was also observed. At the same time, a spike-like increase of cesium recombination continuum and line spectrum appeared just after the load change. Results of the quasi-one dimensional numerical simulation have indicated that the observed overshoot was caused by the following phenomena: 1) a steep reduction of the Hall current and a steep increase in both the Faraday current and the electrical conductivity, and 2) a slow reduction of gas velocity due to the enhanced retarding force. Furthermore, the measured spike-like increase of radiation intensity was ascribed to an increase of electron temperature and electron number density by a steep increase of Joule heating.