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Hydrodynamic scaling and cyclone performance of pressurized circulating fluidized beds.

机译：加压循环流化床的流体动力学结垢和旋风分离器性能。

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We verify the validity of the "reduced set" of four dimensionless parameters proposed by Glicksman et al. (1993) to characterize flows in Pressurized Circulating Fluidized Beds. Although the "reduced set" is valid for viscous and inertial particle drag, we test its appropriateness in the intermediate regime by comparing two series of experiments with different combinations of gases and solids that preserve the "reduced set" but mismatch the complete set of five dimensionless numbers characterizing the flow. We also evaluate the performance of the primary cyclone for both series.; While Archimedes numbers are widely different in the two series, the distribution of particle terminal velocities calculated with the correlations of Haider and Levenspiel (1989) is preserved. Comparisons of the dimensionless profiles of pressure along the flow and solid volume fraction in the radial direction indicate that both data series exhibit similar hydrodynamics in the fully-developed region.; In addition, we find that pressure and radial profiles depend strongly on the solid loading but weakly on the Froude number, and that the gas pressure gradient in the fully-developed region is nearly balanced by the suspension weight, except at the lowest superficial gas velocity. Radial profiles of solid volume fraction relative to the mean across the flow appear independent of conditions. However, the mean solid volume fraction increases with solid loading. These observations are captured by a simple model of the relative velocity between gas and solids that recognizes the crucial role played by solid clusters in this flow.; Finally, we find that pressure losses across the cyclone scale with the gas inlet kinetic energy. Our pressure data are well captured by the model of Muschelknautz and Greif (1997), who predict that pressure losses decrease with increasing solid loading. However, the loading-independent model of Leith and Licht (1972) is better at capturing the overall and grade efficiencies of our primary cyclone.
机译：我们验证了Glicksman等人提出的四个无量纲参数的“约简集”的有效性。 （1993年）来表征加压循环流化床中的流量。尽管“简化集”对粘性和惯性粒子阻力有效，但我们通过比较两个实验的不同系列来测试其在中间状态下的适用性，这些实验使用了保留“简化集”但不匹配五个完整集的气体和固体的不同组合无量纲数字表征流量。我们还评估了两个系列的主旋风分离器的性能。尽管阿基米德数在两个序列中有很大不同，但保留了用Haider和Levenspiel（1989）的相关性计算的粒子末端速度的分布。沿径向和固体体积分数沿径向的无量纲压力分布图的比较表明，两个数据系列在充分发育的区域均表现出相似的流体动力学。此外，我们发现压力和径向轮廓在很大程度上取决于固体载荷，而在较小程度上取决于弗洛德数，并且除了最低的表观气体速度以外，在完全展开区域中的气压梯度几乎由悬浮液重量平衡。 。相对于整个流动的平均值，固体体积分数的径向分布与条件无关。但是，平均固体体积分数随固体负荷而增加。这些观察结果是通过气体与固体之间相对速度的简单模型捕获的，该模型可以识别固体团簇在此流中的关键作用。最后，我们发现整个旋风分离器的压力损失与进气口动能有关。 Muschelknautz和Greif（1997）的模型很好地捕获了我们的压力数据，他们预测压力损失会随着固体载荷的增加而减小。但是，Leith和Licht（1972）的独立于负荷的模型在捕获初级旋风分离器的整体效率和爬坡效率方面表现更好。

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