負荷変化によるディスク形ｍｈｄ発電機の過渡現象

Abstract

The results of an experimental study on transient phenomena in a closed cycle disk MHD generator are described in this paper. The transient phenomena were caused by a steplike change of load resistance during testing of the shock‐tube driven disk MHD generator. The load resistance was varied by using an IGBT (insulated gate bipolar transistor) installed in the load circuit. When the load resistance was changed from 0.096 Ω to 2.5 Ω, 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 spikelike increase of the cesium recombination continuum and line spectrum appeared just after the load change. The results of quasi‐one‐ dimensional numerical simulation indicate 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 the gas velocity due to the enhanced retarding force. Furthermore, the measured spikelike increase of the radiation intensity was ascribed to an increase of electron temperature and electron number density due to a steep increase of Joule heating. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(4): 34–42, 2011; Published online in Wiley Online Library (http://wileyonlinelibrary.com). DOI 10.1002/eej.21004