Abstract: In order to comprehend the performance of hypersonic cold-air MHD power generators with ionization by electron beams, the flow phenomena of a rectangular Faraday type MHD generator with segmented electrode were simulated using three dimensional MHD five-equation model associated with low magnetic Reynolds assumption and a simple model of beam-generated ionization. The effects of the power spent on ionization and the intensity of magnetic field on the performance of the generator were investigated,obtaining the number density of electrons and electrical conductivity formed by the ionization under different ionization spent. The results show that electron beams are capable of generating an adequate conductivity in cold air. When the loading factor is 0.5, electrical efficiency is substantially maintained at between 0.5~0.6, and the intensity of magnetic field has no effect on electrical efficiency. When power spent on ionization is 0.06MW/m³,0.6MW/m³,6MW/m³,0MW/m³, respectively, the conductivity σ(S/m) is 0.28,0.9,3,7,7, respectively. When power spent on ionization is 30MW/m³,the energy extraction rate is 26% and the electrical efficiency is 66%,close to the optimal performance of the generator, corresponding the intensity of magnetic field of 10T. 

Key words: Hypersonic; Electron-Beam-Generated ionization; Magnetohydrodynamics power generation; Segmented electrode; Three-dimensional model

摘要： 为了获得高超声速低温来流条件下基于电子束电离的磁流体发电机性能,采用三维低磁雷诺数磁流体动力学五方程模型和简化的电子束电离模型,对等截面分段法拉第型磁流体发电机内的流动进行数值模拟,研究了电离能量花费、磁场强度对发电通道性能的影响,得出了不同电离花费下电离所形成的电子数密度和电导率。研究结果表明,电子束电离低温来流能够产生足够的电导率,当负载系数保持为0.5时,电效率基本保持在0.5~0.6之间,电效率大小受磁场强度影响不大,电离能量花费P_ion(MW/m³)为0.06,0.6,6,30,300时的电导率σ(S/m)分别为0.28,0.9,3,7,27。当电离能量花费为30MW/m³,能量提取率达到26%,电效率为66%,发电机性能接近最佳, 对应的磁场强度为10T。 

关键词: 高超声速;电子束电离;磁流体(MHD)发电;分段电极;三维模型 