超声波强化换热研究进展

随着科学技术的快速发展，微电子器件在不同领域得到越来越广泛的应用。对于高集成化和高频化的微电子器件，传统的冷却技术已很难满足高效散热的需求，因此对器件的可靠性与安全性带来严重的影响。近年来，研究者提出了多种无源换热过程强化技术，但是这些技术在不同程度上增加了流动阻力从而极大地限制了其应用潜力。超声波技术具有成本低、使用简便、操控灵活、穿透性强和无污染等特点，超声波与散热技术相结合实现有源换热过程强化已逐渐引起研究者的关注和重视。本文对超声波激励换热过程强化的研究进展进行了系统综述，首先介绍超声波强化换热的机理，然后总结并分析超声波技术在单相气体对流、单相液体对流、池沸腾和流动沸腾换热过程中的理论和实验研究，最后讨论超声波换热技术面临的若干挑战并提出未来潜在的发展方向，为构建高性能和实用化超声波换热体系提供相应的参考。 

Research progress on the intensification of heat transfer by ultrasound

Microscale electronic devices offer promising application capabilities in various fields, such as information, aeronautics and astronautics, energy, and chemical engineering. Specifically, the exceptional performance of high-integration and high-frequency devices leads to a significant heat flux enhancement. Conventional air and liquid cooling techniques struggle to meet the efficient heat dissipation requirement, affecting the reliability and safety of microscale electronic devices significantly. Many types of passive heat transfer process intensification strategies have been proposed recently, such as those based on adjusting element structure, surface roughness, surface hydrophobicity, and channel dimension. However, these passive strategies increase flow resistance to some extent, limiting their applicability. Ultrasound has several unique characteristics, including low cost, simple operation, flexible control, strong penetrability, and good biocompatibility. These characteristics make ultrasound a promising candidate for use in national defense, biomedical theranostics, agriculture, food, the environment, and materials. Researchers have paid considerable attention to the integration of ultrasound with heat transfer techniques, which has gradually become one of the key research directions for heat transfer enhancement. This paper aims to provide a comprehensive overview of the research progress on the intensification of the ultrasound-excited heat transfer process. First, the principles of ultrasound-excited heat transfer enhancement are introduced, and two major acoustic phenomena, acoustic cavitation and acoustic streaming, are highlighted. Theoretical and experimental studies on ultrasound-excited single-phase gas convection, single-phase liquid convection, pool boiling, and flow boiling heat transfer process intensification are then summarized, and typical studies in these fields are categorized and discussed in depth. Finally, current challenges and future directions are presented, such as simple numerical simulation models that should consider multiphysics and multidomain constraints for accurately representing the practical heat transfer process, lack of sufficient characterization methods that should develop new and integrated visualization techniques for precisely monitoring heat transfer performance, limited focus on other acoustic phenomena other than acoustic streaming and acoustic cavitation that should provide a comprehensive analysis for revealing the in-depth heat transfer mechanisms, and few attempts and pathways to industrialization that should demand researchers from different disciplines to work together and collaboratively. It is hoped that this review article will not only reveal the unprecedented functionality of ultrasound for heat transfer enhancement but will also provide critical guidelines for the rational and practical design of robust ultrasound heat transfer platforms.