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为了揭示流化床的放大规律,对气固鼓泡流化床进行了数值模拟,考察了流化床放大对流化状态、膨胀比、分布板控制区、气泡特性的影响。结果表明:在表观气速不变,床体等比例放大的条件下,床径增大对流化床的流化状态影响较大,当气速低于临近流化速度时,床径越大,膨胀比越小;当气速高于临近流化速度时,不同床径的膨胀比在1.18-1.48范围内波动;分布板控制区受床径增大的影响较小,不同床径的分布板控制区均在分布板以上10-15mm范围内;随着流化床径增大,气泡上升速度逐渐增加,而气泡初始直径受流化床放大影响较小。
In order to reveal the rule of fluidized bed enlargement, the numerical simulation of gas-solid bubbling fluidized bed was carried out. The effect of fluidized bed enlargement on fluidized state, expansion ratio, controlled area of distribution plate and bubble characteristics was investigated. The results show that under the conditions of the constant apparent air velocity and the enlarged bed, the increase of bed diameter greatly affects the fluidization state of the fluidized bed. When the gas velocity is lower than the adjacent fluidized bed velocity, When the gas velocity is higher than the adjacent fluidization velocity, the expansion ratio of different bed diameters fluctuates in the range of 1.18-1.48. The control area of the distribution plate is less affected by the increase of the bed diameter, and the diameter of the bed The control zone of the distribution plate is within the range of 10-15mm above the distribution plate. As the fluidized bed diameter increases, the bubble rising speed gradually increases, while the initial bubble diameter is less affected by the fluidized bed amplification.