Study of Strong Interaction between Electro-magnetic Field and Flow Field in Coal Direct Fired MHD Power Generators with CO2 Recovery

提出并分析了采用美国POC项目开发的低温电极的燃煤mdd -蒸汽联合CO2回收系统，在考虑制氧和CO2液化所需功率的情况下，可获得45%（基于高热值：HHV）的电厂效率。在这方面，如果采用常规电厂，电厂效率将下降到30%左右。提出并分析了无CO2回收的高性能中汽联合系统，在空气预热温度为1620 K、1780 K和2100 K时，装置效率分别达到50%、55%和60%以上。对实验结果进行了数值分析，其中流体动力学采用隐式TVD格式，采用k- omega湍流模型捕捉冲击，电动力学采用Galerkin有限元法。研究表明，在俄罗斯15mwe脉冲MHD发电机内，产生了大规模的不对称边界层分离和核心流区复杂的激波，实验中发现的输出功率饱和现象是激波和边界层分离引起的。随时间变化的三维分析也已开始。首次发现了10MWe法拉第发电机阴极间击穿现象，由于电磁场与流场之间强烈的三维MHD相互作用，导致电流密度分布的复杂三维结构和电弧电流的分岔现象。

We have proposed and analyzed the coal-fired MHD-steam combined system with CO2 recovery, and revealed that 45 % (on the basis of high heat value : HHV) of plant efficiency can be obtained, which takes into account the power required by oxygen production and CO2 liquefaction, when the low temperature electrodes are used, which have been developed by the USA POC project. In this connection, the plant efficiency will decrease to about 30% when the conventional power plant is used. High performance MI-ID-steam combined systems without CO2 recovery have been also proposed and analyzed, leading to that the plant efficiency becomes 50%, 55%, and more than 60% for the air pre-heating temperature of 1620 K, 1780 K, and 2100 K, respectively.Experimental results have been examined with numerical analyses, where the implicit TVD scheme is implemented for the fluid dynamics with k- omega turbulent model to capture shocks and the Galerkin FEM is used for electrodynamics. It has been shown that a large scale asymmetric boundary layer separation and complicated shock waves at the core flow region are induced within the Russian 15 MWe pulsed MHD generator, and also that the saturation phenomena of output power found in experiments were caused by the shock wave and the boundary layer separation.Time-dependent three-dimensional analyses have also been initiated. It has been found for the first time that phenomena of inter-cathode break-down in 10MWe Faraday generator induce complicated three-dimensional structure of current density distribution and bifurcation phenomena of arc current due to the strong three-dimensional MHD interaction between electro-magnetic field and flow field.