Mixing performance in continuous oscillatory baffled reactors
Mixing performance in continuous oscillatory baffled reactors
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DOI：
10.1016/j.ces.2020.115600
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发表时间：
2020-06-29
影响因子：
4.7
通讯作者：
Aubin, J.
中科院分区：
文献类型：
--
作者：
Avila, M.;Fletcher, D. F.;Aubin, J.
在目前的文献中，关于操作参数对空间混合质量的影响以及如何将二次进料引入连续振荡折流板反应器（COBR）以实现良好的混合质量的信息有限。这项工作首次使用瞬态层流 CFD 模拟探讨了 COBR 中二次进料（被动非反应示踪剂）的位置对空间混合性能的影响。研究了三个理论进料位置，涵盖一系列净流和振荡雷诺数（Re-net = 6 - 27/Re-o = 24 - 96），选择范围以确保流场在所有情况下保持二维。通过使用 Alberini 等人开发的区域分布方法分析示踪剂的空间均匀性来评估宏观混合。 （2014a）。由于再循环涡流有助于径向混合，在反应器壁处或第一挡板边缘上游引入二次流极大地提高了混合质量。然而，在中心线引入二次进料会导致高轴向分散和有限的径向混合。通过适当的引入位置，混合质量通常随着速度比的增加而提高。然而，如果净流量太低，混合性能就会降低，因为二次流被推到挡板的上游，在那里它不能从流量再循环中受益。 (C) 2020 Elsevier Ltd. 保留所有权利。
In the current literature, there is limited information on the influence of operating parameters on spatial mixing quality and how a secondary feed should be introduced into continuous oscillatory baffled reactors (COBR) to achieve good mixing quality. This work explores for the first time the impact of the position of a secondary feed (passive non-reactive tracer) on spatial mixing performance in a COBR using transient laminar CFD simulations. Three theoretical feed positions are studied covering a range of net flow and oscillatory Reynolds numbers (Re-net = 6 - 27/Re-o = 24 - 96), the range being chosen to ensure that the flow field remains two-dimensional in all cases. Macromixing is evaluated by analysing the spatial uniformity of the tracer with the areal distribution method developed by Alberini et al. (2014a). Introduction of the secondary stream at the reactor wall or upstream of the edge of the first baffle greatly improves mixing quality due to the recirculation eddies, which assist radial mixing. However, introduction of the secondary feed at the centreline results in high axial dispersion with limited radial mixing. With an adequate introduction position, mixing quality typically increases with an increment in the velocity ratio. Nevertheless, if the net flow is too low, mixing performance decreases because the secondary stream is pushed upstream of the baffles, where it does not benefit from flow recirculation. (C) 2020 Elsevier Ltd. All rights reserved.