EMMS模型中噎塞判据的进一步分析

Further Analysis on the Choking Criteria in the EMMS Model

噎塞是气固流态化系统中典型的结构突变现象。能量最小多尺度(energy minimization multi-scale,EMMS)模型能够从机理上分析此现象。本文讨论了EMMS模型中现有的两种噎塞判据之间的联系与区别,结果表明在相同气体速度下二者得到的饱和夹带量近似相等;进一步分析表明它们所反映的物理机理具有一致性,都确定了快速流态化和稀相输送间流域过渡的临界条件。

Choking is a typical critical phenomenon in gas-solid fluidization featuring abrupt structural changes. The energy minimization multi-scale （EMMS） model is capable of analyzing the mechanism of this phenomenon. In this paper, two criteria for choking previously proposed on the basis of the EMMS model are discussed with the emphasis on the difference and consistency between them. Simulation result shows that the saturation carrying capacities calculated with the two criteria are approximately equivalent at given gas velocities. It is demonstrated further that the mechanism reflected by these two criteria is consistent. Both criteria have defined the critical condition for the regime transition between fast fluidization and dilute transport.