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Drag reduction of Solid-liquid Suspension Using Macro-agglomeration Structure induced by Shear flow

利用剪切流引起的宏观团聚结构减阻固液悬浮液

基本信息

批准号：
15560146
负责人：
GOTOH Kuniaki
金额：
$ 2.37万
依托单位：
OKAYAMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15560146/
关键词：
Multiphase flow Particle Agglomeration Flow resistance Pressure drop Drag reduction

项目摘要

It is known that a surfactant solution with appropriate counter ion induces the structure of fiber-like micelles in a shear flow field. When the structure is induced, the drag of the pipe flow is reduced. Based on the fact, we presumed that structure of agglomerated particles in a particle suspension also causes the same effect. Thus, we attempted to reduce the pressure drop of the suspension flow by adding a polymer flocculant. In this study, we investigated the change of the pressure drop of the pipe flow with the flocculant concentration. The change of the drag was evaluated by the drag reduction rate defined by the ratio of the difference of the friction factor between water flow and suspension flow to the friction factor of water flow.It was found that the suspension with polymer flocculant caused the drag reduction under the conditions of particle concentration 1 and 10vol%. In the same flocculant concentration, the water solution of the flocculant (=without particles) also cause … More d the drag reduction. However, the drag reduction rate of the solution was less than that of the suspension with flocculant under certain conditions. The fact shows that the particle enhances the drag reduction.The effect of the flocculant on the drag reduction decreases with time. One of the main causes is the cut of polymer chain by a shear flow field and/or by the equipment like a pump. It was found that the adding a flocculant into a particle suspension causes larger enhancement than the adding particles into the flocculant solution. It leads to an assumption that inhomogeneous agglomeration attributes to the enhancement. Thus, it was expected that the change of agglomeration from inhomogeneous to homogeneous is another cause of the decrease of the effect.From the observation of the flocculate in a stationary fluid, it was found that independent agglomerations were formed when the drag reduction was enhanced. The fact shows that the drag reduction is attributed by agglomerated particles. It leads to an expectation that the drag reduction can be achieved in any other solid-liquid suspension if proper agglomeration is formed. Less

已知具有适当抗衡离子的表面活性剂溶液在剪切流场中诱导纤维状胶束的结构。当结构受到诱导时，管流的阻力减小。基于这一事实，我们推测颗粒悬浮液中附聚颗粒的结构也会产生相同的效果。因此，我们尝试通过添加聚合物絮凝剂来降低悬浮液流的压降。在本研究中，我们研究了管流压降随絮凝剂浓度的变化。通过减阻率来评价阻力的变化，减阻率定义为水流与悬浮液流的摩擦因数之差与水流摩擦因数的比值。结果发现，含有聚合物絮凝剂的悬浮液在颗粒浓度1和10vol%的条件下引起了减阻。在相同的絮凝剂浓度下，絮凝剂的水溶液（=不含颗粒）也会引起减阻。但在一定条件下，溶液的减阻率小于添加絮凝剂的悬浮液的减阻率。事实表明，颗粒增强了减阻作用。絮凝剂的减阻效果随时间的延长而减弱。主要原因之一是剪切流场和/或泵等设备切断聚合物链。发现将絮凝剂添加到颗粒悬浮液中比将颗粒添加到絮凝剂溶液中产生更大的增强。它导致了一种假设，即不均匀的聚集归因于增强。因此，预计团聚体从不均匀到均匀的变化是效果降低的另一个原因。通过对静止流体中絮凝体的观察，发现当减阻增强时，会形成独立的团聚体。事实表明，减阻是由于颗粒团聚所致。这导致人们期望，如果形成适当的团聚，则可以在任何其他固液悬浮液中实现减阻。较少的