Mixing of viscous non‐Newtonian fluids plays an important role in many industrial processes (wastewater treatment, methanization, etc.). In some cases, mixing by gas injection can be more interesting than mechanical mixing. The present study focuses on the gas injection in yield stress fluids. The influence of the air flow rate, fluid rheological properties, and geometrical configuration on an air jet impinging the bottom wall of a tank containing a yield stress fluid has been considered. Focus has been placed on the air cavity present at the injection point. The trends of two key parameters of the cavity have been characterized: its maximum diameter and frequency detachment. Correlations based on the characteristic dimensionless numbers governing the flow have been derived. These correlations show that the apparent viscosity has an effect on the cavity's frequency but a low influence on its diameter which is mainly governed by the air flow inertia.

中文翻译：

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屈服应力流体中的注气

粘性非牛顿流体的混合在许多工业过程（废水处理，甲烷化等）中起着重要作用。在某些情况下，通过注气进行的混合比进行机械混合更有趣。本研究的重点是屈服应力流体中的气体注入。已经考虑了空气流速，流体流变性质和几何形状对撞击包含屈服应力流体的罐的底壁的空气射流的影响。焦点已放在注射点处的气腔上。腔的两个关键参数的趋势已被表征：其最大直径和频率分离。基于控制流量的特征无量纲数，得出了相关性。