Li Wenming, Yang Siyan, Chen Yongping, Li Chen, Wang Zuankai
Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, 210096, PR China.
Department of Mechanical Engineering, Hong Kong Polytechnic University, Hong Kong, PR China.
Nat Commun. 2023 Jul 6;14(1):3996. doi: 10.1038/s41467-023-39289-5.
Two-phase (liquid, vapor) flow in confined spaces is fundamentally interesting and practically important in many practical applications such as thermal management, offering the potential to impart high thermal transport performance owing to high surface-to-volume ratio and latent heat released during liquid/vapor phase transition. However, the associated physical size effect, in coupling with the striking contrast in specific volume between liquid and vapor phases, also leads to the onset of unwanted vapor backflow and chaotic two-phase flow patterns, which seriously deteriorates the practical thermal transport performances. Here, we develop a thermal regulator consisting of classical Tesla valves and engineered capillary structures, which can switch its working states and boost its heat transfer coefficient and critical heat flux in its "switched-on" state. We demonstrate that the Tesla valves and the capillary structures serve to eliminate vapor backflow and promote liquid flow along the sidewalls of both Tesla valves and main channels, respectively, which synergistically enable the thermal regulator to self-adapt to varying working conditions by rectifying the chaotic two-phase flow into an ordered and directional flow. We envision that revisiting century-old design can promote the development of next generation cooling devices towards switchable and very high heat transfer performances for power electronic devices.
受限空间内的两相（液体、蒸汽）流在本质上很有趣，并且在许多实际应用中具有重要的实际意义，例如热管理，由于其高的表面积与体积比以及液/汽相变过程中释放的潜热，具有实现高传热性能的潜力。然而，相关的物理尺寸效应，再加上液相和汽相之间比容的显著差异，也会导致不希望出现的蒸汽回流和混沌两相流模式的出现，这严重降低了实际的传热性能。在此，我们开发了一种由经典特斯拉阀和工程化毛细结构组成的热调节器，它可以切换其工作状态，并在其“开启”状态下提高其传热系数和临界热通量。我们证明，特斯拉阀和毛细结构分别起到消除蒸汽回流和促进液体沿特斯拉阀和主通道侧壁流动的作用，这协同使热调节器能够通过将混沌两相流整流为有序的定向流来自适应不同的工作条件。我们设想，重新审视百年前的设计能够推动下一代冷却装置的发展，使其朝着具有可切换和极高传热性能的功率电子设备方向发展。
