Flow of Elastic Liquids

弹性液体的流动

• 批准号: RGPIN-2015-06338
• 负责人: James, David
• 金额: $ 1.82万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=590997
• 关键词: Flow; Elastic; Liquids

The proposal concerns liquids containing a dissolved polymer, which generally makes the liquid elastic as well as viscous. Polymers are often added to liquids to make the material more viscous – paint and ink are examples – but the polymer also makes the liquid elastic, and this additional fluid property can affect a flow. In inkjet printing, for example, the ink’s elasticity can cause unwanted satellite droplets. Sometimes the polymer is added solely for the improvement provided by elasticity. Two well-developed applications are: to agricultural spraying because elasticity improves surface deposition of the coating; and to turbulent pipe flow because elastic stresses reduce the driving pressure. The amount of added polymer is often minute but the effect can be dramatic. In turbulent pipe flow, for instance, the addition of 10 parts per million can reduce the required pressure by 50%. Viscosity is an obvious property of a fluid - liquids are referred to as thick or thin - but elasticity is generally much less evident. The most visible manifestation is probably stringiness, as seen with saliva and egg whites.

该提案涉及含有溶解聚合物的液体，该聚合物通常使液体具有弹性和粘性。 通常将聚合物添加到液体中以使材料更加粘稠（例如油漆和墨水），但聚合物也会使液体具有弹性，并且这种额外的流体特性会影响流动。 例如，在喷墨打印中，墨水的弹性可能会产生不需要的卫星液滴。 有时添加聚合物仅仅是为了改善弹性。 两个成熟的应用是：农业喷涂，因为弹性改善了涂层的表面沉积；以及湍流管流，因为弹性应力会降低驱动压力。 添加的聚合物的量通常很小，但效果却可以是显着的。例如，在湍流管流中，添加百万分之十可以将所需压力降低 50%。 粘度是流体的一个明显属性 - 液体被称为粘稠或稀薄 - 但弹性通常不太明显。 最明显的表现可能是粘性，如唾液和蛋清所示。