基于新型直接接触式储热的熔融PCM射流破碎机理研究

The blocking of heat transfer fluid (HTF) by the solidification of materials is one of the significant issues for the conventional direct contact thermal energy storage (DCTES). In view of the above issue, this study takes the novel DCTES, i.e. ejecting molten material into HTF to make heat transfer with breakup particles, as the application background and focuses on the research of molten jet breakup. The research contents are as follows: investigation on shape characteristic of jet and distribution function of particle diameter; evaluation on the jet parameters and study on the regression model; discussion on instability of surface wave and prediction model of jet. The shape characteristic of molten jet was indicated with the analysis. The accurate function on the description of diameter distribution was obtained. The grade of parameters influencing on jet was known. The dispersion equations and prediction model were established for the description of jet breakup. The law on influencing instability of jet by the dimensionless number was revealed. The issue on the blocking of HTF for the conventional DCTES will be solved by the implementation of this project. The study will also lay a theoretical foundation for the development of novel thermal energy storage technology.

储热材料凝固后对换热工质流动的阻碍问题是传统直接接触式储热技术的瓶颈之一。本项目针对上述问题，以熔融储热材料在换热工质内射流破碎，形成颗粒化换热的新型直接接触式储热为背景，以熔融储热材料的射流破碎为研究对象，开展了如下内容研究：射流破碎形态特性与破碎粒径分布函数研究；影响射流破碎的参数评价及参数回归模型研究；射流破碎表面波的不稳定性与破碎预测模型研究。通过深入分析，探索熔融储热材料的射流形态特性，获得描述破碎粒径分布的准确函数，明确影响射流破碎参数的等级，构建射流破碎的色散方程和预测模型，揭示表征射流破碎无量纲数对射流不稳定性的影响规律。本项目的成功实施将有助于解决传统直接接触式储热面临的流动阻碍问题，并为新的储热技术开发提供理论基础。

传统储放热过程中存在的储热材料导热困难和直接接触式储放热过程中存在的凝固堵塞问题，制约了新型储热技术的创新和发展。本项目创新地提出了一种新型储放热方法，即利用射流破碎作用将熔融态的相变储热材料PCM（Phase Change Material）以颗粒形态分散在导热介质中，从而极大程度上增加了PCM与导热介质接触的比表面积，不仅显著提高了储热器的换热效率，并且PCM以颗粒状分散在储热器内也解决了大块PCM的堵塞问题。本项目通过深入分析，探索熔融储热材料的射流形态特性，获得描述破碎粒径分布情况，明确影响射流破碎参数的等级，构建射流破碎的色散方程，揭示表征射流破碎无量纲数对射流不稳定性的影响规律。本项目的成果包括发表SCI论文5篇，授权发明专利2项，实用新型专利1项。