Collaborative Research: Dynamics and Stability of Metallic Foams: Network Modelling

该奖项的研究目标是开发一种通过冻结液体/气体泡沫来制造多孔金属构件的方法和理论。液体泡沫的一个主要问题是，相邻的气泡非常迅速地(毫秒)结合在一起，将泡沫变成一个大气泡。在这项研究中，将设计并模拟一个连续的过程，它冻结在适当的位置上的气泡，在固体中形成均匀的气孔阵列。要做到这一点，必须研究液体泡沫中的流体流动和热传递，确定不同物理过程发生的速率，并设计出控制这些过程的协议。将构建多泡泡沫的数学表示，以监测泡沫是如何变粗的，并确定冻结材料的最佳方法。渐近方法、数值模拟和分析将结合起来，建议进行实验，以产生该过程的概念证明。如果成功，这项工作有望创造出一种多孔金属，其强度与可比固体相同或更强，但重量只有同类固体的十分之一。这种材料将用于飞机、火箭、船舶和汽车的制造。这项研究将使金属具有精确控制的孔隙率，并将影响对复杂的、非线性的物理现象的理解，这些现象由包含大范围尺度的自由边界问题支配。这项研究对社会的潜在和长期影响将包括提高能源效率、环境清洁度、安全性和节约物质资源。该项目由材料加工与制造(MPM)计划、土木、机械和制造创新(CMMI)部门、流体动力学计划、化学、生物工程、环境和运输系统(CBET)部门以及工程局(ENG)提供的资金共同资助，以支持部门间研究。

The research objective of this award is to develop a process and theory for making members of porous metals by the freezing of liquid/gas foams. A primary problem with liquid foams is that adjacent bubbles coalesce very rapidly (milliseconds) turning the foam into one large bubble. In this investigation a continuous process that freezes the bubbles in place creating a uniform array of pores within the solid will be designed and modeled. To accomplish this one must study the fluid flow and heat transfer in liquid foams, determine the rates at which different physical processes occur and devise a protocol for the control of these. A mathematical representation of a multi-bubble foam will be constructed to monitor how the foam coarsens and to determine the best way to freeze the material. Asymptotic methods, numerical simulation and analysis will be combined to suggest experiments to yield proof of concept of the process. If successful this work is expected to result in a process to create porous metals that are as strong or stronger than the comparable solid but with one-tenth the weight. Such materials would be useful in the manufacture of airplane, rockets, ships, and automobiles. This research will enable the creation of metals of precisely controlled porosity and will impact the understanding of complex, nonlinear physical phenomena governed by free boundary problems containing a large expanse of scales. The potential, long-term impact of the research in society will include improvements in energy efficiency, environmental cleanliness, safety, and conservation of material resources. This project is jointly funded by the Materials Processing & Manufacturing (MPM) Program, of the Civil, Mechanical, and Manufacturing Innovation (CMMI) Division, by the Fluid Dynamics Program, of the Chemical, Bioengineering, Environmental, and Transport Systems (CBET) Division, and by funding provided from the Directorate for Engineering (ENG) to support Inter Divisional Research.