Study of Strong Interaction of Coal-Fired MHD Power Generator with CO2 Recovery as Large-Scale Concentrated Power Source

为了实现高性能的CO2回收磁流体发电机，我们开发了含时二维和三维Navier-Stokes方程以及稳态二维和三维麦克斯韦方程的数值分析程序。采用Harten-Yee迎风TVD方法求解Navier-Stokes方程，该方法可以捕捉到强激波，并采用并行计算来减少计算时间，而采用线性四面体单元的有限元方法求解麦克斯韦方程.三维分析结果表明，在喷管与绝热体之间沿磁场方向产生了强斜激波，冲击波向下传播到出口，对MHD发电机的性能影响很大，这是二维分析无法得到的结果。结果还表明，在MHD发电机内产生的激波与电流分布有很强的关系，并引起较大的边界层分离，本文还研究了磁流体发电机通过逆变系统与交流电网的相互作用，发现磁流体发电机可以提供电能并初步提出了采用强制换相逆变器系统可以通过有功功率和无功功率的同时控制来稳定交流电网。

We have developed numerical analysis codes for the time-dependent two-and three-dimensional Navier-Stokes Equations together with the steady two-and three-dimensional Maxwell Equations with a turbulence model in order to realize a high performance MHD generator with CO2 recovery. The Navier-Stokes Equations are solved with the Harten-Yee upwind TVD method, which can capture strong shock waves and a parallel computation is used to reduce the computation time, whereas the Maxwell Equations are solved with the finite element method with linear tetrahedron elements.Results obtained by the three-dimensional analyses showed that strong oblique shock waves were induced between the nozzle and insulator in the magnetic field direction, and the shock waves propagate downwards to the exit, resulting in a large influence on the MHD generator performance, which could not be obtained with the two-dimensional analyses. It was also revealed that the shock wave induced within MHD generators had a strong relation with the electric current distribution and a large boundary layer separation was induced, resulting in a large pressure loss when the MHD generator was operated with a high current density.We also studied the interaction between the MHD generator and the AC power grid through inverter systems and found that the MHD generator could provide the electric power to the grid, and also preliminarily that introduction of forced commutated inverter systems could stabilize the AC grid by means of simultaneous control of the active and reactive power.