ELECTRODE TEMPERATURE EFFECT ON MHD GENERATOR PERFORMANCE.
STANFORD UNIV CALIF INST FOR PLASMA RESEARCH
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Five segmented electrode pairs capable of controlled temperatures between 700K and 1700K were mounted at the downstream end of the MHD channel. The temperature of the electrode wall upstream of the electrode was controlled at two values, 750K and 2400K. By means of probes mounted in the sidewall, it was possible to measure the voltage drop at the electrodes due to the combined boundary layer and surface-sheath effects. Results showed that hot electrodes performed considerably better than cold electrodes and that anode voltage losses were largely due to boundary-layer losses while cathode losses were caused by boundary-layer and surface-sheath effects. Computer calculations were made to show the effect of electrode size for three types of gas conductivity profiles corresponding to no thermal boundary-layer and cold and hot boundary-layers. Spectroscopic measurements of the boundary-layer temperature showed that the profile could be represented by a power-law enthalpy profile with the exponent equal to 18. An experiment was made to determine if finite recombination rates had a significant effect in combustion MHD generators. Techniques were investigated for measuring electron temperature and number density in combustion gas plasmas. Author
- Electric Power Production and Distribution