Fundamentals of soft thermofluidic system design
Fundamentals of soft thermofluidic system design
复制标题
软热流系统设计基础
DOI：
10.1039/d0sm00504e
复制
发表时间：
2020
期刊：
影响因子：
3.4
通讯作者：
Rykaczewski, Konrad
中科院分区：
文献类型：
--
作者：
Kotagama, Praveen;Manning, Kenneth C.;Rykaczewski, Konrad
许多天然热流体系统的柔软成分使它们能够通过动态改变形状（例如，我们皮肤附近的毛细血管扩张或收缩）有效地移动热量并控制其传输速率。到目前为止，制造类似的可变形“软热流体系统”受到具有合适机械性能的材料的低导热率的限制。尽管添加了填料，但弹性体复合材料仍保持柔软和可拉伸，具有由液态金属微滴增强的导热性，为该应用提供了理想的材料。在这项工作中，我们使用这些材料来开发一个基本的热流体系统，该系统由一个柔软的发热管组成，该发热管通过水流进行内部冷却，并探索其热行为，因为它经历了很大的形状变化。瞬态器件形状变化使热设计中采用的许多传统假设失效，使得对该器件的操作进行分析成为一项重要的任务。为此，使用时间尺度分析，我们证明了当传统的假设打破和突出条件下，准静态假设是适用的。在这种渐进的形状调制机制中，致动器件在给定拉伸下的热行为接近具有等效几何形状的静态器件的热行为。我们通过实验表征我们的软系统的热流体行为来验证这种时间尺度分析，因为它在操作过程中以不同的频率经历轴向周期性的伸缩。通过这样做，我们探索了多种形状调制制度，并提供了一个理论基础，可用于设计的软热流体系统进行瞬态变形。
The soft composition of many natural thermofluidic systems allows them to effectively move heat and control its transfer rate by dynamically changing shape (e.g. dilation or constriction of capillaries near our skin). So far, making analogous deformable “soft thermofluidic systems” has been limited by the low thermal conductivity of materials with suitable mechanical properties. By remaining soft and stretchable despite the addition of filler, elastomer composites with thermal conductivity enhanced by liquid-metal micro-droplets provide an ideal material for this application. In this work, we use these materials to develop an elementary thermofluidic system consisting of a soft, heat generating pipe that is internally cooled with flow of water and explore its thermal behavior as it undergoes large shape change. The transient device shape change invalidates many conventional assumptions employed in thermal design making analysis of this devices’ operation a non-trivial undertaking. To this end, using time scale analysis we demonstrate when the conventional assumptions break down and highlight conditions under which the quasi-static assumption is applicable. In this gradual shape modulation regime the actuated devices’ thermal behavior at a given stretch approaches that of a static device with equivalent geometry. We validate this time scale analysis by experimentally characterizing thermo-fluidic behavior of our soft system as it undergoes axial periodic extension–retraction at varying frequencies during operation. By doing so we explore multiple shape modulation regimes and provide a theoretical foundation to be used in the design of soft thermofluidic systems undergoing transient deformation.