Performance of a Seed-free Disk Magnetohydrodynamic Generator with Self-excited Joule Heating in the Nozzle
Performance of a Seed-free Disk Magnetohydrodynamic Generator with Self-excited Joule Heating in the Nozzle
复制标题
喷嘴自激焦耳加热的无种子盘磁流体动力发电机的性能
DOI：
10.1109/tps.2017.2654514
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Y.Okuno
中科院分区：
文献类型：
--
作者：
M.Tanaka;Y.Okuno
在无籽晶惰性气体盘形磁流体发电机中，采用二维r-z数值模拟方法研究了喷嘴区自激焦耳热对发电机性能的影响。工作气体（纯惰性气体）可以有效地电离的协助下，自激焦耳加热的喷嘴位于上游的发生器通道，即使是一个小的，外部施加的预电离功率（PP）。在喷嘴中的电离度的增加和在发电机通道中的最佳电导率的减少，随着磁通量密度的增加，减少了使净焓提取（EE）比最大化的最佳PP。对于典型的氩盘磁流体发电机，在磁通密度为4 T时，当PP为0.3%时，最大净EE比为25%，等熵效率为65%。由于阳极边缘附近的电流浓度，喷嘴中的电离度的增强和等离子体在垂直方向上的不均匀性对于具有较高电离率的氩和氙比对于氦更显著。
In a seed-free inert-gas disk-shaped magnetohydrodynamic (MHD) generator, the effect of the self-excited Joule heating in the nozzle region on the generator performance has been examined with 2-D r-z numerical simulations. The working gas (pure inert gas) can be ionized efficiently with the assistance of the self-excited Joule heating in the nozzle located upstream of the generator channel, even for a small, externally applied preionization power (PP). The increase in the ionization degree in the nozzle and the decrease in the optimum electrical conductivity in the generator channel with increase in the magnetic flux density reduce the optimum PP that maximizes the net enthalpy extraction (EE) ratio. For a typical argon disk MHD generator, a maximum net EE ratio of 25% and an isentropic efficiency of 65% can be obtained at a small PP of 0.3% of the inflow enthalpy under a magnetic flux density of 4 T. The enhancement of the ionization degree in the nozzle and the inhomogeneity of the plasma in the vertical direction because of the current concentration near the anode edge are more marked for argon and xenon, with their higher ionization rates, than for helium.