Development of Plasma Disk MHD Generator with High Performance

在1995年，我们研究了MHD通道中的压力损失的机制，主要是降低发电效率，使用我们已经准备好的等离子体MHD发电机。结果表明，压力损失主要发生在超声速喷管中，该喷管位于磁流体发生器的上游区域。还知道，这种压力损失是由于流体的动能主要转移到等离子体的热量中，而几乎没有转移到提取的电功率中。此外，我们进行了发电实验的压力和铯种子分数的许多条件下，找到了一个最佳的条件，使发电机效率最大。在此基础上，我们设计并研制了一种新型的发电机，并得到了该基金的资助。1996年，我们开始使用这种新发电机进行实验，并试图获得接近实际所需目标值的更高效率。结果，以氩气为工作流体的磁流体发电机的效率的世界最高纪录被建立。该发电机还记录了具有相同横截面积比的发电机中的最高焓提取。同时获得了100 MW/m^3的功率密度。总之，在此科研资助项目的基础上，我们成功地提高了磁流体发电机的性能，获得了许多重要的工程知识。为了使等离子体磁流体发电技术进入商业化阶段，还需要进行更大规模的示范试验。可以说，通过这种试验取得经验，就有可能达到商业化阶段。

In 1995, we studied the mechanism of pressure loss in the MHD channel which mainly decreased the efficiency of electrical power generation, using a plasma MHD power generator we had already prepared. As a result, It was clarified that the pressure loss was induced mainly in the supersonic nozzle which was lecated in the upstream region of the MHD generator. It wa also known that this pressure loss was caused because the kinetic energy of fluid was transferred mainly into the heat addition to the plasma, hardly into the extracted electrical power. Further, we conducted the power generation experiments on many conditions of pressure and cesium seed fraction and found an optimum condition of them of which the generator efficiency made maximum. At the same time, our highest power density of 110MW/m^3 was recorded.Based on these experimental results, a new generator was designed and ste up, supported by this grant. In 1996, we started a experiment using this new generator and tried to obtain the higher efficiency near the target value practically required. As a result, world highest record of the efficiency of the MHD generator using argon as working fluid was established. This generator also recorded the highest enthalpy extraction in generators which had the same cross-sectional area ratio. At the same time, the power density of 100MW/m^3 was obtained. Additionally, we found and clarified several new physical phenomena.In summary, we succeeded in increasing the performance of the MHD power generator remarkably and obtained much important knowledge in engineering, based on this grant-in-aid for Scientific Research. In order to reach the commercialization stage of plasma MHD power generation, the demonstration tests using larger facility will be needed. We can say that it will be possible to reach the commercialization stage by getting experiences on these kind of tests.