State Key Laboratory of High-performance Precision Manufacturing, Department of Mechanical Engineering, Dalian University of Technology, Dalian 116024, China.
State Key Laboratory of High-performance Precision Manufacturing, Department of Mechanical Engineering, Dalian University of Technology, Dalian 116024, China.
J Colloid Interface Sci. 2023 Aug 15;644:315-324. doi: 10.1016/j.jcis.2023.04.098. Epub 2023 Apr 25.
The vacuum method is a widely adopted technique for eliminating bubbles from polymers containing particles. To investigate the influence of bubbles on the behavior of particles and the concentration distribution in high-viscosity liquids under negative pressure, experimental and numerical methods have been employed. The experimental findings demonstrated a positive correlation between the diameter and rising velocity of bubbles and the negative pressure. As the negative pressure increased from - 10 kPa to - 50 kPa, the position of the region where the particles were concentrated in the vertical direction was elevated. Furthermore, when the negative pressure exceeded - 50 kPa, the particle distribution became sparse and layered locally. The Lattice Boltzmann method (LBM) integrated with the discrete phase model (DPM) was utilized to investigate the phenomenon, and the outcomes revealed that rising bubbles have an inhibitory effect on particle sedimentation, and the extent of inhibition was determined by the negative pressure. In addition, vortexes generated by differences in the rising velocity between bubbles resulted in a particle distribution that was sparse and layered locally. This research provides a reference for achieving desired particle distributions using a vacuum defoaming approach and should be further studied to extend its applicability to suspensions containing particles with different viscosities.
真空法是一种广泛采用的技术，用于从含有颗粒的聚合物中消除气泡。为了研究气泡对颗粒行为和高粘度液体中浓度分布的影响，采用了实验和数值方法。实验结果表明，气泡的直径和上升速度与负压呈正相关。随着负压从-10kPa 增加到-50kPa，颗粒在垂直方向上集中的区域位置升高。此外，当负压超过-50kPa 时，颗粒分布局部变得稀疏和分层。利用格子玻尔兹曼方法（LBM）与离散相模型（DPM）相结合来研究这一现象，结果表明，上升的气泡对颗粒沉降有抑制作用，抑制程度取决于负压。此外，由于气泡上升速度的差异而产生的涡流导致局部颗粒分布稀疏和分层。这项研究为使用真空消泡方法实现所需的颗粒分布提供了参考，应该进一步研究以扩展其在含有不同粘度颗粒的悬浮液中的适用性。
