Gas dispersion in non‐Newtonian fluids is a challenging task due to the formation of large cavities behind the impeller blades, which leads to the generation of very large bubbles. In this study, the effects of impeller speed, impeller type, pumping direction, and CMC concentration on the local and overall gas holdup inside a coaxial mixing tank comprised of two central impellers and an anchor were investigated through tomography, computational fluid dynamics (CFD), and response surface methodology (RSM). The results showed that an increase in the fluid apparent viscosity resulted in decreasing the gas holdup except for the pitched blade impeller in upward‐pumping mode. Although the highest overall gas holdup was accomplished for the downward pumping and co‐rotating mode, the local gas holdup data revealed a non‐uniform distribution of gas by this configuration. The lowest gas dispersion efficiency was achieved by a system comprised of two Scaba impellers and an anchor.

中文翻译：

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包含非牛顿流体的充气同轴混合系统中的局部和整体气体滞留量

非牛顿流体中的气体扩散是一项艰巨的任务，因为在叶轮叶片后面会形成大的空腔，从而导致产生非常大的气泡。在这项研究中，通过层析成像，计算流体力学（CFD），研究了叶轮速度，叶轮类型，泵送方向和CMC浓度对由两个中央叶轮和一个锚组成的同轴混合罐内局部和整体气体滞留量的影响。 ，以及响应面方法（RSM）。结果表明，流体流体表观粘度的增加导致气体滞留量的减少，除了斜泵叶轮在向上泵送模式下。尽管向下抽气和同向旋转模式实现了最高的总气体滞留量，当地的天然气含气量数据显示，此配置导致气体分布不均匀。由两个Scaba叶轮和一个锚组成的系统实现了最低的气体分散效率。