液态金属磁流体发电机电枢反应分析

Armature Reaction Analysis for Liquid Metal Magnetohydrodynamic Generator

为研究液态金属磁流体(LMMHD)发电机内部感生电流产生的感应磁场对外部永磁磁路的影响,采用3D有限元法分析了不同感生电流下LMMHD发电机的磁路分布特点、永磁体工作点磁密及工作气隙磁密分布规律,得到了LMMHD发电机电枢反应特性。结果表明,LMMHD发电机内电枢电流产生的感应磁场使工作气隙磁场发生畸变,永磁体产生去磁效应,铁磁部件磁通密度增大、甚至达到磁饱和,磁路漏磁增大;当外磁路已达到磁饱和,电枢反应磁场减小工作气隙有效磁场分量、增大工作气隙端部漏磁,且在工作气隙中间区域产生Y方向磁场分量(电枢电流为X方向)。

To research the effect of the armature reaction on the applied permanent magnet of a liquid metal magnetohydrodynamic（ LMMHD） generator,the 3D finite element method is adopted to calculate and analyze the magnetic field＇s distribution,permanent magnet＇s flux density working point,and the working air-gap flux density under different armature currents in order to find out the armature reaction characteristics of the LMMHD generator. The results show that the induced magnetic field generated by the armature current distorts the working air-gap magnetic field, causes the magnetic saturation of the ferromagnetic parts, enlarges the magnetic flux leakage,and produces serious demagnetization effect in the permanent magnet. The effective magnetic field in the working air-gap decreases and the end leakage magnetic field increases with an armature current when the applied magnetic field reaches the magnetic saturation. There also presents the Y-direction magnetic field in the middle area of the working air-gap with an X-direction armature current.