High speed microfluidic jets can be generated by a thermocavitation process: from the evaporation of the liquid inside a microfluidic channel, a rapidly expanding bubble is formed and generates a jet through a flow focusing effect. Here, we study the impact and traversing of such jets on a pendant liquid droplet. Upon impact, an expanding cavity is created, and, above a critical impact velocity, the jet traverses the entire droplet. We predict the critical traversing velocity (i) from a simple energy balance and (ii) by comparing the Young–Laplace and dynamic pressures in the cavity that is created during the impact. We contrast the model predictions against experiments, in which we vary the liquid properties of the pendant droplet and find good agreement. In addition, we assess how surfactants and viscoelastic effects influence the critical impact velocity. Our results increase the knowledge of the jet interaction with materials of well-known physical properties.

中文翻译：

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微流体射流对悬垂液滴的影响

高速微流体射流可以通过热空化过程产生：微流体通道内的液体蒸发，形成快速膨胀的气泡，并通过流动聚焦效应产生射流。在这里，我们研究了这种射流对悬垂液滴的影响和穿越。在撞击时，会产生一个膨胀的空腔，并且在超过临界撞击速度时，射流穿过整个液滴。我们通过简单的能量平衡和（ii）通过比较冲击过程中产生的空腔中的杨-拉普拉斯压力和动态压力来预测临界横移速度（i）。我们将模型预测与实验进行了对比，在实验中我们改变了悬滴的液体特性并找到了很好的一致性。此外，我们评估了表面活性剂和粘弹性效应如何影响临界冲击速度。我们的结果增加了对射流与已知物理特性材料相互作用的了解。