Study on Performance of Environmentally Benign and High Efficiency Plasma MHD Generator under Continuous Operation

发展环境友好、高效的电厂对减少二氧化碳排放、节约能源具有重要意义。本文以等离子体磁流体发生器为研究对象，对盘式磁流体发生器的超音速闭环系统的性能进行了研究。闭环系统是磁流体动力装置的主要系统，惰性气体在闭环系统内循环。在本实验中，使用了Ar作为工质。实验结果总结如下：在2.4小时内成功地进行了高温(&gt；1900K)Ar循环。对换热器的换热效率进行了研究，发现在换热器能量效率较高的情况下，扩散器和排气风道的散热量较大。热损失较大的原因是扩散器和排气风道处的水冷却。同时，提出了提高换热系数的建议。在换热系数增大四倍的假设下，计算出的Ar温度和热损失与实验值吻合较好。对环路内的压比进行了讨论，结果表明，喷管喉部上游的总压由总温和质量流量决定。另一方面，下游的总压力由回路中的总质量和上游的总压力决定。进行了发电实验，观察到负载电阻与霍尔电压之间有很好的相关性。然而，功率输出仍然很小。

The development of environmentally benign and highly efficient power plant is important to reduce CO2 emission and to save energy resources. The present research was focused on a plasma MHD generator, and performances of the supersonic closed loop with the disk MHD generator were investigated. The closed loop is a major system in the MHD power plant, and noble gas circulates inside the closed loop. In the present experiment, argon was used as working fluid. Experimental results are summarized as follows.The high temperature (>1900K) argon circulation was carried out successfully during 2.4 hours. The heat gain and loss of argon was investigated, and a large heat loss was found at the diffuser and the exhausting duct although an energy efficiency of recuperator was high. The large heat loss was ascribed to water cooling at the diffuser and the exhausting duct. At the same time, the enhancement of heat transfer coefficient was suggested. The argon temperature and the heat loss calculated under an assumption of four times larger heat transfer coefficient have shown a good agreement with experimental ones. The pressure ratio inside the loop was discussed, and the result has indicated that the total pressure at the upstream of nozzle throat is decided by the total temperature and the mass flow. On the other hand, the total pressure at the downstream is determined by the total mass in the loop and the total pressure at the upstream. The power generation was carried out, and a good correlation between the load resistance and the Hall voltage was observed. However, the power output remained very small.