内循环三相流化床反应器内部流场的CFD数值模拟

CFD Simulation of Internal Flow Field of Three-Phase Fluidized Bed Reactor with Internal Circulation

摘要: 应用CFD技术和Euler三相流模型对内循环三相流化床反应器内部流场进行数值模拟，分析讨论了反应器中气含率、固含率及液速的分布及其成因。结果表明反应器中气含率、固含率及液速具有显著不同的特征。相对于降流区，反应器升流区气含率径向分布显著不均匀，但随轴向高度的增加分布不均匀性有所改善，其最大值对称于中心轴线附近，降流区气含率径向分布虽然比较均匀，但气含率远远小于升流区。降流区和升流区固含率径向分布均呈现环核结构特点，即固含率径向分布峰值位于边壁附近，而中心区固含率径向分布相对均匀，且不同轴向高度的径向分布形式接近。升流区液速呈中心大边壁小的特点，但随轴向高度增加径向分布趋于均匀，降流区液速分布呈明显的套管环隙流动特征。

Abstract: The distribution of gas hold up, solid hold up, liquid velocity in riser and downcomer the reactor was simulated by CFD method. The results showed that: the radial distribution of gas hold up was bigger at the center area and became smoother with the rise of the axial height, while the peak value was in the vicinity of the center axis. The average value of gas hold up increased with in-creasing axial height and became a constant value ultimately. The radial distribution of solid hold up in riser was larger in center and wall area, and had a larger wall region in downcomer also due to the wall effect. The radial distribution of liquid velocity in riser was faster in the center region and smaller on the draft tube wall. But with the increase of the axial height, the difference becomes smaller. The downcomer liquid velocity radial distribution had a typically pipe flow character.