用于功能热流体的相变材料微胶囊力学性能研究进展

相变材料微胶囊悬浮液用作传热流体时, 具有传热温差小、载热密度高、储放热时间短等突出优点, 但在研究和应用实践中常发现微胶囊经若干次泵送循环后严重变形、塌陷甚至破损, 引起相变物质泄漏、聚结、黏壁、堵塞管路等后果, 使体系性能显著恶化。为使这种悬浮液性能更稳定、循环寿命更长, 本文综述了从微胶囊自身力学性能和循环流动稳定性两方面开展的实验和理论研究工作进展, 认为微胶囊自身力学性能是影响其循环稳定性的内因, 泵送作用是导致微胶囊破裂的主要外因。总结了两方面研究存在的问题, 指出相关研究应朝规范测试表征方法、拓展研究客体范围、充分利用数值模拟技术等方向发展, 使该领域的研究更加深入。

Research progress in mechanical properties of microencapsulated phase change materials used as functional thermal fluid

When microencapsulated phase change materials (MicroPCM) slurry is used as heat transfer fluid, the slurry has smaller temperature difference of heat transfer, higher heat carrier density, shorter heat storage/release time than common heat transfer fluid. However, during research and practical application, MicroPCM particles may be severely deformed, sunk or even damaged after a certain number of pumping cycles, which further causes PCM leakage, coalescence, sticky wall, clogging pipes and other consequences, and thus, leads to a significant deterioration in slurry performance. To make this slurry have more stable performance and longer cycle life, some experimental and theoretical researches, on both the mechanical properties of MicroPCM themselves and their circulation flow stability in slurry, are carried out at home and abroad. In this paper, related research progresses are reviewed. It is believed that the mechanical properties of MicroPCM themselves and the pumping effects are the intrinsic and external factors of circulation flow stability respectively. This paper also summarizes problems that exist in both aspects and puts forward that relevant researches should be implemented to develop standardized testing and characterization methods, to expand the scope of research object, to take full advantage of numerical simulation technology.