Flow of complex fluids

复杂流体是指含有悬浮颗粒或溶解聚合物链的液体，它们通常导致的流动行为与水和汽油等简单流体截然不同。一些常见的复合液体是洗发水、番茄酱和血液，一些工业上重要的液体是油漆和农业喷雾剂。这些粘弹性流体的总体目标是了解其基本物理特性，表征流动阻力，并建立描述性方程。我的具体目标是表征拉伸或伸长运动的流动阻力，因为剪切阻力已经很好地建立了。在最近的工作中，我们开发了一种技术来测量几乎没有弹性的液体（如喷墨油墨）的拉伸阻力。该新技术已获得专利，并已被证明可用于粘合剂纸上的液体增白剂，从而提高了造纸效率。我们现在想把这项技术应用于其他几乎没有弹性的液体，如油漆，目标是使新的“改进”配方在实验室进行评估，而不是在生产线上试用。

Complex fluids are liquids containing suspended particles or dissolved polymer chains, which generally cause flow behaviour to be frustratingly different than that of simple fluids like water and gasoline. Some common complex fluids are shampoo, ketchup and blood, and some industrially important ones are paints and agricultural sprays. The general objective with these viscoelastic fluids is to understand the underlying physics, to characterize the flow resistance, and to develop the descriptive equations. My specific objective is to characterize the flow resistance to stretching or elongational motion, for shearing resistance has already been well established. In recent work toward the objective, we developed a technique to measure the stretching resistance of barely elastic liquids such as inkjet inks. The novel technique was patented and has been proven useful for the liquid whitener applied on bond paper, enabling improved efficiency in papermaking. We now want to apply this technique to other barely elastic liquids such as paints, with the goal of enabling new 'improved' formulations to be evaluated in the laboratory instead of trying them on the production line.