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气体物性对流化床中流体结构有着重要影响,是流化床反应器设计和放大的关键参数。本文应用基于细网格的双流体模型,研究了不同气体作为流化介质在不同气速下对流化床中固体浓度分布以及床层膨胀高度的影响。研究结果表明,气体密度和粘度的增大有利于均匀流化;气体的粘度相对于密度对流动特性的影响更为重要。在本文的模拟条件下,随气速增大不同气体流化的床层膨胀高度增加程度较为接近。模拟结果还直观的展示了鼓泡流态化中典型气泡的运动和形变过程,并结合对气泡附近的气体和固体流场的分析,讨论了气泡运动过程中气体内部之间和气体与固体之间的质量交换行为。
Gas physical properties of fluidized bed fluid structure has an important influence on the fluidized bed reactor design and amplification of the key parameters. In this paper, a two-fluid model based on a fine grid is used to study the effect of different gases as fluidizing medium on the concentration distribution of solid in a fluidized bed and the height of bed expansion at different gas velocities. The results show that the increase of gas density and viscosity is conducive to uniform fluidization; the viscosity of gas relative to the density of the flow characteristics of the more important. Under the simulation conditions of this paper, the increase of expansion height of bed with different gas fluidization is close with the increase of gas velocity. The simulation results also show the typical bubble movement and deformation process in the bubbling fluidization. Combining with the analysis of the gas and solid flow in the vicinity of the bubble, the influence of gas and solid Between the quality of exchange behavior.