充液弹性毛细管低温相变的力学分析

充液弹性毛细管广泛存在于生物体（如毛细血管、植物导管等）和工程领域（如微流控冰阀门、制冷系统热管、MEMS微通道谐振器等）.低温工作环境中，充液弹性毛细管内部的液柱会发生相变并引发冻胀效应，从而导致管壁的变形、损伤乃至断裂.该文建立并求解了考虑温度梯度、界面张力及液体冻胀作用的弹性毛细管平衡方程，分析了液柱低温相变过程中毛细管壁的径向和环向应力，发现管壁应力分布受热毛细弹性数和冻毛细弹性数的影响，且影响大小跟壁厚相关.该研究不仅有助于理解生物体内充液弹性毛细管冻胀失效机制，还可为MEMS微流控芯片的抗冻胀失效设计提供理论指导.

Mechanics of Low-Temperature Phase Transition in Liquid-Filled Elastic Capillary Tube

Liquid-filled elastic capillaries are a kind of standard component in life body (e.g., capillary blood vessel and plant vessel) and engineering fields (e.g., MEMS microchannel resonators and heat pipes). Under sufficiently low-temperature, the liquid in a capillary tube will undergo a phase transition and exhibit a frozen-heave effect, which may cause deformation, damage, and even fracture of the tube wall. In this study, we established the governing equation of an elastic capillary tube, with temperature gradient, interfacial tension, and frozen-heave effect accounted for, and solved the equation for stresses developed in the tube wall during freezing. It is demonstrated that stress distribution in tube wall is influenced by the thermoelastocapillary number and the freezeoelastocapillary number, both dependent upon wall thickness. Results obtained in this study are not only helpful for understanding the prevention of frozen-heave failure, but also provide theoretical guidance for tailoring the freezing resistance of microfluidic devices used in MEMS.