论文标题
通过磁性限制减少液体阻力
Fluid drag reduction by magnetic confinement
论文作者
论文摘要
粘性液体流量的摩擦力是一个主要的能源损失问题，并且严重限制了微流体的实际用途。将这种阻力减少了几百分之几，仍然是虚幻的。在这里，我们展示了圆柱液体液体流量如何导致亚MM和MM大小的通道的阻力减少60-99％，而不管运输液体的粘度是否比包裹的液体更大或小。与润滑或护套流相反，我们不需要封装润滑剂的连续流，这里由磁力固定在适当的铁氟纤维组成。在具有适当边界条件的层流模型中，我们引入了一个修改后的雷诺数，其缩放尺度取决于几何因素和两种液体的粘度比。它解释了我们的整个数据范围，并揭示了用于优化拖放值的关键设计参数。因此，我们的结果为微流体设计的途径开辟了途径，其压力梯度可能会通过大小降低。
The frictional forces of a viscous liquid flow are a major energy loss issue and severely limit microfluidics practical use. Reducing this drag by more than a few tens of percent remain illusive. Here, we show how cylindrical liquid-in-liquid flow leads to drag reduction of 60-99% for sub mm and mm sized channels, irrespective of whether the viscosity of the transported liquid is larger or smaller than that of the encapsulating one. In contrast to lubrication or sheath flow, we do not require the continuous flow of the encapsulating lubricant, here made up of a ferrofluid held in place by magnetic forces. In a laminar flow model with appropriate boundary conditions, we introduce a modified Reynolds number with a scaling that depends on geometrical factors and viscosity ratio of the two liquids. It explains our whole range of data and reveal the key design parameters for optimizing the drag reduction values. Our results therefore open the route to microfluidics designs with pressure gradients possibly reduced by orders of magnitudes.
