IMPROVEMENT OF PLASMA MHD GENERATOR PERFORMANCE BY OPTIMIZATION OF CHANNEL GEOMETRY

objective of present study is an improvement on performance of The plasma MHD generator which isexpected to provide very high thermal efficiency.In fiscal 1997effects of an area ratio on a relation between the isentropic efficiency and the enthalpy extractionwere investigated experimentally and an optimization of the area ratio was also made. As a result，最高isentropic efficiency was achieved and it was 46.5% . At the same time，the highest power density of 140mw /m D13 D13 was demonstrated. the experiments have indicated thata high isentropic efficiency required for a commercial power plant is only for the DiskMHD generator with a small area rio . an introduction of an inlet swirl was adopted in fiscal 1998A new concept was adopted to the design of the swirlvane, and in order to design the swirl vanesthree-dimensional numerical simulation was carried. The simulation indicated that thin swirl vanesare useful to reduce fluid-dynamical loss. In the experiments with the inlet swirl，enthalpy extraction was improved remarkably and as a result，the highest isentropic efficiency increased up to 54.3% . This is the highest for the plasma MHDgenerator.In fiscal 1999behavior of flow field and plasma in the MHD generator was investigated and a lot of important data数据已被证明是一个大的可能swirl和一个高的Mach number werekept in the MHD generator and this led to the high isentropic efficiency. the present study hasencouraged us to proceed to the next step in which an achievement of higher performances than thepresent ones是一个主要对象。

The objective of present study is an improvement on performance of the plasma MHD generator which is expected to provide very high thermal efficiency.In fiscal 1997, effects of an area ratio on a relation between the isentropic efficiency and the enthalpy extraction were investigated experimentally and an optimization of the area ratio was also made. As a result, the highest isentropic efficiency was achieved and it was 46.5 %. At the same time, the highest power density of 140 MW/mィイD13ィエD1 was demonstrated. The experiments have indicated that a high isentropic efficiency required for a commercial power plant is possible only for the Disk MHD generator with a small area ratio.An introduction of an inlet swirl was adopted in fiscal 1998 in order to improve the enthalpy extraction. A new concept was adopted to the design of the swirl vane, and in order to design the swirl vanes, three-dimensional numerical simulation was carried. The simulation indicated that thin swirl vanes are useful to reduce fluid-dynamical loss. In the experiments with the inlet swirl, the enthalpy extraction was improved remarkably and as a result, the highest isentropic efficiency increased up to 54.3 %. This is the highest for the plasma MHD generator.In fiscal 1999, behavior of flow field and plasma in the MHD generator was investigated and a lot of important data was accumulated. The data have suggested that a large positive swirl and a high Mach number were kept in the MHD generator and this led to the high isentropic efficiency. The present study has encouraged us to proceed to the next step in which an achievement of higher performances than the present ones is a main objective.