Application of a modified line reversal temperature measurement system to coal-fired MHD plasmas

The application of the modified line reversal technique for measurements of the plasma temperature of coal-fired magnetohydrodynamic power generators is studied.

The optical system employed is analyzed to allow its effects to be included into the general modified line reversal equations. Furthermore, the size of images produced by the optical system are obtained and used to calculate measured temperature inaccuracies due to mis-alignment of the optics. The analysis of the optical system is used to characterize the error produced by slag-blocked optical ports.

Plasma temperature measurements were made under a variety of thermodynamic conditions. The temperature measurements made with the modified line reversal apparatus were supplemented with simplified plasma luminosity measurements. In conjunction with the modified line reversal temperature, the luminosity measurements allowed calculation of temperature profiles.

The experimental results were used to analyze the operation of the modified line reversal apparatus and to obtain estimates of the errors introduced by the low temperature boundary layer and particles in the flow stream.

The major results of the investigation are the criteria found to be important in the design of the optical system and the conclusion that the modified line reversal technique is suitable for coal-fired flows.