Temperature measurement of noble and combustion gas plasmas with optical measurement system for MHD generators

A measurement of temperature of plasmas is important to analyze the operation conditions in a channel of a magnetohydrodynamic (MHD) generator and an MHD accelerator. The MHD generator is expected as a highly effective device for an electrical power generation system. For the capability in the high output power density, the MHD generator is applied to a power supply for an application of a scramjet engine. While the MHD accelerator is one of candidates in a propulsion device for interplanetary exploration. For the efficient operation of those MHD devices, the plasma conditions should be analyzed, and optimized. In this paper, we measure the plasma temperature of noble and combustion gasses by using an optical measurement system. The optical temperature measurement system is based on the spectral line reversal method, and consists of a light source (halogen lump), a chopper, an interference filter, and a photo multiplier. In the case of temperature measurement of inert gas plasma, the shock tube is used for the plasma generation. On the other hand, the combustion gas plasma is generated using a model rocket engine. As an experimental result, we measured the temperature of 3000 K for the noble gas plasma driven by the shock tube. The temperature was increased during 20 ms at the stagnation point. For the combustion gas plasma, the temperature of 1800 K is observed during 0.8 s.