基于格子Boltzmann方法的喷雾冷却过程液滴冲击与相变传热机理研究

Spray cooling, a heat removal technology with phase change, has attracted much attention in recent years because of its advantages such as high dissipating capability, uniformity of heat removal, low coolant demand, and broad prospect in engineering applications. However, owing to its dependence on many parameters, the heat transfer mechanisms during spray cooling are still poorly understood. In the proposed project, the lattice Boltzmann method, which is a mesoscopic numerical approach and has distinct advantages in modeling multiphase flows and phase change heat transfer, is employed to study the liquid-gas two-phase flow and phase change heat transfer in spray cooling. Specifically, model construction, model verification, and high-performance numerical computations will be carried out jointly to study the droplet impingement on boiling liquid film and hot surface during spray cooling, exploring the influences of the interaction between the droplet and the boiling film on bubble growth and the phase change heat transfer as well as the influences of the hot surface structure and mixed wettability on droplet evaporation and boiling in the liquid film, so as to reveal the effects of different factors during the processes of droplet impingement on liquid film and hot surface as well as the mechanism of phase change heat transfer enhancement in the related processes. The results will provide theoretical basis and guidance for the engineering applications of the spray cooling technology.

喷雾冷却作为一种含相变的散热技术，因其散热能力强、散热均匀、工质需求量小、应用前景广阔等优点，在近年来受到广泛的关注。但由于喷雾冷却的过程受到许多因素的影响，其传热机理仍未得到全面的认识。本项目拟采用格子Boltzmann方法，一种在多相流与气液相变模拟方面具有独特优势的介观数值模拟方法，研究喷雾冷却中的气液两相流动与相变传热。具体地，通过采用理论建模、模型校核和高性能数值计算相结合的研究方案，研究喷雾冷却中液滴冲击沸腾液膜和热表面的过程，探索液滴与液膜表面和膜内沸腾之间的相互作用对气泡生长和相变传热的影响，以及热表面的结构和复合湿润性表面对液滴蒸发和液膜内沸腾的影响，以期揭示液滴冲击液膜和热表面的过程中不同因素的影响规律以及相关过程中强化相变换热的机制。研究结果将为喷雾冷却技术的工程应用提供理论依据和指导。

喷雾冷却作为一种含相变的散热技术，因其散热能力强、散热均匀、工质需求量小、应用前景广阔等优点，在近年来受到广泛的关注。但由于喷雾冷却的过程受到许多因素的影响，其传热机理仍未得到全面的认识。本项目采用格子Boltzmann方法，一种在多相流与气液相变模拟方面具有独特优势的介观数值模拟方法，研究了喷雾冷却中蒸发与沸腾过程中的气液两相流动与相变传热。具体地，研究了亲疏水复合湿润性平直表面上的液滴蒸发，揭示了液滴蒸发过程中三相接触线的“粘-滑-跳”机制，基于相界面宽度的尺度揭示了三相接触线附近的表面特性对液滴行为的决定作用；构建了三维的气液相变格子Boltzmann模型，研究了复合湿润性表面上的液滴蒸发，揭示了环形图案化表面与条纹图案化表面上液滴蒸发的动态行为与特征：研究了结构化表面上湿润性差驱动的液滴迁移行为，数值揭示了湿润性差影响液滴迁移行为的机制；研究了表面微结构与复合湿润性共同作用下的沸腾传热特性，探索了复合湿润性表面强化核沸腾的机制，揭示了复合湿润性对微结构表面上沸腾传热的影响；研究了结构化复合湿润性表面亲水区域的接触角大小及微结构尺寸（微结构高、宽等）对沸腾相变传热的影响。在Progress in Energy and Combustion Science（IF：25.242）、Langmuir、Physical Review E、International Journal of Heat and Mass Transfer、Applied Thermal Engineering等国际著名权威刊物上发表第一作者/通讯作者SCI论文10篇（标注了本项目的基金编号），其中1篇第一作者论文入选ESI高被引论文及ESI热点论文（前0.1%）；应邀于第六届亚洲计算传热与计算流体会议作了题为“Lattice Boltzmann methods for multiphase flow and liquid-vapor phase change: Theory & applications”的大会主题报告。