Development of Plasma Disk MHD Generator with High Performance

1995年，我们利用已研制的等离子体磁流体发电装置，研究了磁流体通道中主要降低发电效率的压力损失的机理。结果表明，压力损失主要发生在位于磁流体发生器上游的超音速喷管内。我们还知道，造成这种压力损失的原因是，流体的动能主要转移到等离子体的热量中，而很少转移到提取的电能中。在此基础上，进行了多种压力和铯晶种含量条件下的发电实验，找到了发电效率最高的最佳条件。与此同时，我们的最高功率密度达到了110 mW/m^3。在这些实验结果的基础上，我们设计了一台新的发电机，并在这笔赠款的支持下进行了调试。1996年，我们开始了使用这种新发电机的实验，并试图获得接近实际所需的目标值的更高效率。结果，创造了以Ar为工质的MHD发电机效率的世界最高纪录。在具有相同横截面面积比的发电机中，该发生器还记录了最高的焓提取。同时获得了100 mW/m~3的功率密度。此外，我们还发现并澄清了一些新的物理现象。综上所述，我们成功地提高了磁流体发电机的性能，并在工程上获得了许多重要的科学知识。为了达到等离子体MHD发电的商业化阶段，还需要利用更大的设施进行示范试验。可以说，通过积累这类测试的经验，将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.