在液体悬浮桥快速拉伸过程中,固体粒子增强了界面不稳定性
Philipp Brockmann1, Max Lannert1, Hatim Ennayar1
1Institute of Fluid Mechanics and Aerodynamics, Technische Universitat Darmstadt, Darmstadt 64287, Germany. brockmann@sla.tu-darmstadt.de.
Soft matter
|August 4, 2025
概括
在这项研究中,在拉伸液体桥梁中的固体颗粒显著增加了界面不稳定性和线索形成. 颗粒积累和干扰驱动指纹,中间颗粒大小产生最多的次要桥梁.
科学领域:
- 流体动力学和风病学
- 合体和表面科学科学
- 材料科学 材料科学 材料科学
背景情况:
- 研究液体桥在快速拉伸下的行为对于理解各种工业过程至关重要.
- 粘性液体的界面不稳定性可能导致复杂的现象,如指纹和线程形成.
- 悬浮粒子在修改这些不稳定性的作用需要详细的实验研究.
研究的目的:
- 实验研究悬浮液体桥的快速拉伸动力学和界面不稳定性.
- 为了阐明固体颗粒大小和体积分数对桥梁稳定性和导线形成的影响.
- 确定在拉伸过程中导致不稳定性和二次桥梁形成的机制.
主要方法:
- 利用高速视频系统观察液体桥梁在平行板之间以加速运动 (高达160米/s-2) 拉伸.
- 悬浮中的初始间隙宽度 (3060微米) 和颗粒大小 (630微米) 不同.
- 采用粒子图像速度计 (PIV) 来测量流场并识别粒子驱动机制.
主要成果:
- 与牛顿式液体相比,悬浮液体桥梁的指纹形成增加,这不仅仅是由于有效的粘度变化.
- 粒子促进了众多的二次桥梁 (线程),中间尺寸 (15微米) 最大化了它们的数量.
- 颗粒堆积阻碍了半径的运动,导致早期的指纹不稳定;由于颗粒的堵塞驱动了线材的形成,导致流量分离.
结论:
- 固体颗粒显著破坏伸展液体桥梁的稳定性,通过积累和堵塞促进界面不稳定性和线丝形成.
- 颗粒大小和体积分数对二次桥梁的数量和分布具有关键的影响.
- 由颗粒堵塞引起的流量分离被确定为这些悬浮物中灯丝形成的主要机制.
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