论文标题
用粒状悬浮液探测散布滴剂的耗散
Probing dissipation in spreading drops with granular suspensions
论文作者
论文摘要
在本文中，我们研究了固体表面上密度匹配的颗粒悬浮液的液滴的扩散。粒度分布的差异性丰富了通过突出润湿动力学的关键元素来从单分散实验得出的结论。在所有情况下，尽管存在粒子的存在，但动态接触角与接触线的速度之间的关系均与简单流体的关系相似。我们从这种关系中提取了与大容量中测量的悬浮液的明显润湿粘度。由实验测量支持的维数分析得出了液滴内部区域大小的估计，其中动态接触角的值取决于粘性耗散和毛细血管应力的平衡。根据粒径与此粘性截止长度的比较，对于确定表观润湿粘度的值似乎至关重要。使用双峰混合物，粒度比可以用来显示接触线处局部结构和体积分数的影响，这既影响相应的润湿粘度的值。
In this article, we study the spreading of droplets of density-matched granular suspensions on the surface of a solid. Bidispersity of the particle size distribution enriches the conclusions drawn from monodisperse experiments by highlighting key elements of the wetting dynamics. In all cases, the relation between the dynamic contact angle and the velocity of the contact line follows a similar relation as that of a simple fluid, despite the complexity introduced by the presence of particles. We extract from this relation an apparent wetting viscosity of the suspensions that differs from that measured in the bulk. Dimensional analysis supported by experimental measurements yields estimate of the size of the region inside the droplet where the value of the dynamic contact angle depends on a balance of viscous dissipation and capillary stresses. Depending on how particle size compares with this viscous cut-off length seems crucial in determining the value of the apparent wetting viscosity. With bimodal blends, the particle size ratio can be used to show the effects of the local structure and volume fraction at the contact line, both impacting the value of the corresponding wetting viscosity.
