GOALI: Coating of Rotating Discrete Objects

将液体膜涂覆到非平坦离散物体上出现在各种各样的产品的制造中，例如汽车和航空航天部件、医疗植入物、三维打印部件和食品。 通常需要涂层来保护或功能化表面，甚至是创建最终产品本身。 它是美国制造业的重要组成部分。这个赠款机会学术联络与产业（GOALI）研究促进国家繁荣在这一关键领域，同时开发新的科学见解到一个复杂的问题。与平坦基底上的液膜涂覆相比，在基本水平上理解非平坦离散物体上的液膜涂覆具有相当大的挑战性。 对于大多数应用，需要厚度均匀的涂层。然而，由物体旋转、物体曲率、重力、粘度、表面张力和惯性引起的力之间的复杂相互作用可能导致不稳定性的增长，从而导致涂层不均匀性。 该项目的总体目标是使用理论，实验和工业互动的结合，以显着推进旋转离散物体上的液膜流动的基本理解。 这项工作旨在建立的一般原则为工业涂层工艺的系统设计和优化提供了坚实的基础，从而实现未来的突破，以满足关键的行业需求。 该项目将理论、实验和工业互动相结合，以显著推进对液体流变学、非圆形截面和末端效应如何影响旋转离散物体上液膜流动的基本理解。 该理论涉及广义牛顿液体和粘弹性液体的有限差分和有限元模拟。模拟产生的涂层膜厚度和稳定性限制的函数的参数表征的旋转速度，物体形状，和，流变性能的预测。 这些预测，沿着基本方程的渐近分析，被用来生成标度律，提供对工业从业者有帮助的快速和准确的估计。 实验涉及使用具有非圆形横截面的三维打印物体和具有与模拟中使用的流变模型一致的流变特性的液体的流动可视化。 薄膜厚度的变化和发病的不稳定性推断的可视化和理论预测相比。 理论、实验和工业相互作用之间的相互作用最终促进了物理理解，并产生了可应用于离散物体涂层制造过程的一般原则。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Coating of liquid films onto non-flat discrete objects arises in the manufacturing of a broad variety of products such as automobile and aerospace components, medical implants, three-dimensional printed parts, and foodstuffs. Coatings are often needed to protect or functionalize surfaces, or even to create the final product itself. It is an essential element in American manufacturing. This Grant Opportunity for Academic Liaison with Industry (GOALI) research promotes national prosperity in this critical area while developing new scientific insights into a complex problem. In contrast to liquid-film coating on flat substrates, liquid-film coating on non-flat discrete objects is considerably more challenging to understand at a fundamental level. For most applications, a coating of uniform thickness is desired. However, the complex interplay between forces arising from object rotation, object curvature, gravity, viscosity, surface tension, and inertia may lead to the growth of instabilities and thus coating non-uniformities. The overall objective of this project is to use a combination of theory, experiment, and industrial interaction to significantly advance fundamental understanding of the flow of liquid films on rotating discrete objects. The general principles that the work aims to establish provides a firm foundation for systematic design and optimization of industrial coating processes, thereby enabling future breakthroughs that address critical industry needs. Industrial outreach and involvement of undergraduate students from underrepresented groups complement the research activities.This project uses a combination of theory, experiment, and industrial interaction to significantly advance fundamental understanding of how liquid rheology, non-circular cross sections, and end-effects influence the flow of liquid films on rotating discrete objects. The theory involves finite-difference and finite-element simulations of generalized Newtonian liquids and viscoelastic liquids. The simulations yield predictions of coating-film thickness and stability limits as function of parameters characterizing rotation velocity, object shape, and, rheological properties. These predictions, along with asymptotic analysis of the underlying equations, are used to generate scaling laws that provide quick and accurate estimates helpful for industrial practitioners. The experiments involve flow visualizations using three-dimensional printed objects having non-circular cross sections and liquids having rheological properties consistent with the rheological models used in the simulations. Film-thickness variations and the onset of instabilities are inferred from the visualizations and compared to the theoretical predictions. The interplay between theory, experiment, and industrial interaction ultimately advances physical understanding and lead to general principles that can be applied in manufacturing processes involving the coating of discrete objects.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.