Effect of electrostatic forces on the distribution of drops in turbulent channel flows
Effect of electrostatic forces on the distribution of drops in turbulent channel flows
复制标题
静电力对湍流通道流中液滴分布的影响
DOI：
10.1063/1.5119925
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发表时间：
2019-10
影响因子：
4.6
通讯作者：
Grétar Tryggvason
中科院分区：
文献类型：
--
作者：
Min Lu;Jiacai Lu;Ying Zhang;Grétar Tryggvason
通过直接数值模拟研究了静电力对槽道湍流中液滴分布的影响。液滴和悬浮液被假定为泄漏的介电流体。我们将电导率比（R = σi/σo）设置为小于介电常数比（S−1 = ei/eo），以驱动液流从液滴极点流向它们的赤道。结果表明，外加电场对合金的微观组织和流动性能有显著影响。对于没有电场的流动，其中梅森（Mn）数是无穷大的，在通道的核心和液体流向速度聚集的液滴是类似于单相流中的那些。对于Mn = 0.1，低电场强度，由于液滴界面上的不平衡电力，大部分液滴被驱动到壁。对于Mn = 0.05，液滴更可能粘在一起，因为液滴之间的电流体动力学效应和介电泳力的更强组合。因此，在通道中间的液滴数量增加，而仍然有许多液滴在壁层中。对于Mn = 0.007，电强度非常强，并且沟道中的所有液滴倾向于排成一行并形成跨越沟道宽度的柱。当水流驱使它们彼此靠近时，这些柱变得不稳定。研究还发现，电场强度的增加会导致平均壁面剪应力的增加。此外，当Mn = 0.007时，液体流向速度变得更加均匀，意味着系统的有效粘度增加。通过直接数值模拟研究了静电力对槽道湍流液滴分布的影响。液滴和悬浮液被假定为泄漏的介电流体。我们将电导率比（R = σi/σo）设置为小于介电常数比（S−1 = ei/eo），以驱动液流从液滴极点流向它们的赤道。结果表明，外加电场对合金的微观组织和流动性能有显著影响。对于没有电场的流动，其中梅森（Mn）数是无穷大的，在通道的核心和液体流向速度聚集的液滴是类似于单相流中的那些。对于Mn = 0.1，低电场强度，由于液滴界面上的不平衡电力，大部分液滴被驱动到壁。当Mn = 0.05时，液滴更容易粘在一起，因为液滴之间的电流体动力学效应和介电泳力的结合更强。
The effect of electrostatic forces on the distribution of drops in turbulent channel flows is examined by direct numerical simulations. The droplets and suspending fluid are assumed to be leaky dielectric fluids. We set the electrical conductivity ratio (R = σi/σo) smaller than the dielectric permittivity ratio (S−1 = ei/eo) to drive the flow from the drop poles to their equators. The results show that an applied external electric field has a significant effect on the microstructure and the flow properties. For flows without an electric field, where the Mason (Mn) number is infinity, the drops aggregated in the core of the channel and the liquid streamwise velocity are similar to those in single-phase flow. For Mn = 0.1, a low electric intensity, most of the drops are driven to the walls due to the unbalanced electric force on the drop interface. For Mn = 0.05, drops are more likely to stick together because of the stronger combination of electrohydrodynamic effect and dielectrophoretic force between drops. Therefore, the number of drops in the middle of the channel increases while still many drops are in the wall layer. For Mn = 0.007, the electric intensity is very strong and all the drops in the channel tend to line up and form columns spanning the channel width. These columns become unstable when the flow drives them close to each other. It is also found that an increase of the electric intensity can lead to an increase in the average wall shear stress. In addition, the liquid streamwise velocity will become more uniform, which means the effective viscosity of the system is increased, when Mn = 0.007.The effect of electrostatic forces on the distribution of drops in turbulent channel flows is examined by direct numerical simulations. The droplets and suspending fluid are assumed to be leaky dielectric fluids. We set the electrical conductivity ratio (R = σi/σo) smaller than the dielectric permittivity ratio (S−1 = ei/eo) to drive the flow from the drop poles to their equators. The results show that an applied external electric field has a significant effect on the microstructure and the flow properties. For flows without an electric field, where the Mason (Mn) number is infinity, the drops aggregated in the core of the channel and the liquid streamwise velocity are similar to those in single-phase flow. For Mn = 0.1, a low electric intensity, most of the drops are driven to the walls due to the unbalanced electric force on the drop interface. For Mn = 0.05, drops are more likely to stick together because of the stronger combination of electrohydrodynamic effect and dielectrophoretic force between drop...
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影响因子：
4.1
作者：
S. O. Unverdi;G. Tryggvason
通讯作者：
S. O. Unverdi;G. Tryggvason
DOI：
10.1016/0166-6622(88)80170-7
发表时间：
1988
期刊：
Colloids and Surfaces
影响因子：
--
作者：
Spencer E. Taylor
通讯作者：
Spencer E. Taylor
影响因子：
2.7
作者：
Jiacai Lu;G. Tryggvason
通讯作者：
Jiacai Lu;G. Tryggvason
影响因子：
27.7
作者：
MELCHER, JR;TAYLOR, GI
通讯作者：
TAYLOR, GI
影响因子：
4.6
作者：
Arturo Fernández
通讯作者：
Arturo Fernández