电场强化固液相变传热介观建模及机理研究

Electrohydrodynamics (EHD) is the study of the dynamics of electrically charged fluids (containing ions, solid particles, droplets, etc.) and related heat transfer phenomena. A significant heat transfer enhancement in phase change process can be observed by utilizing ETHD related techniques under low power consumption. However, due to the complexity of its mathematical model, none relevant theoretical analysis or numerical simulation results has been found. Therefore, in this project, we plan to conduct a comprehensive study on solid-liquid phase change in the presence of electrohydrodynamic forces from four aspects: (1) to analyze the mechanisms of the generation of free space charge and its transport at the solid phase, liquid phase and phase interface, and to derive mathematical model of the convection and solid phase extraction phenomena driven by electric forces; (2) to analyze flow instability and high frequency oscillation in liquid phase by applying the linear stability analysis method; (3) to build a numerical model based on mesoscopic lattice Boltzmann method, and to simulate the ETHD phase change problems from two-dimensional parallel-plates model to three-dimensional complex geometries with multiple charges; (4) to conduct experimental tests to verify the effect of ETHD enhancement solid-liquid phase change, and to explore the optimum experimental setup to improve heat transfer efficiency. This project will establish an effective theoretical analysis mehod, a numerical simulation platform and an experimental database for ETHD enhanced solid-liquid phase change problem, and may provide technical support for the innovative application of electric field-based heat transfer enhancement.

电热流体动力学（ETHD）描述电场作用下含有带电粒子（离子、固体颗粒、液滴等）流体的动力学及热学现象。基于电场的新型主动固液相变强化技术，在低电能消耗下可达到显著的强化传热效果，然而由于其数理模型的复杂性，尚未发现相关理论分析或数值模拟研究。本项目拟针对电场强化固液相变过程进行介观建模和理论研究：(1)分析空间自由电荷产生及其在固相、液相和相界面的输运机制，导出电场力驱动对流及固相萃取两种机制的数学模型；(2)引入线性稳定性分析方法，分析液相区流动不稳定性和高频振荡现象；(3)建立基于介观格子Boltzmann方法的数值模型，给出从二维平板到三维复杂形状、多种电荷下的模拟结果；(4)发展有效的实验手段，验证电场强化传热效果并探索强化传热优化方案。该研究将建立起电场强化固液相变问题有效的理论分析方案、数值模拟平台及实验数据库，为基于电场的强化传热传质创新应用提供技术支撑。

电热流体动力学（ETHD）描述电场作用下含有带电粒子（离子、固体颗粒、液滴等）流体的动力学及热学现象。基于电场的新型主动固液相变强化技术，在低电能消耗下可达到显著的强化传热效果，然而由于其数理模型的复杂性，尚未发现相关理论分析或数值模拟研究。本项目针对电场强化固液相变过程进行介观建模、稳定性分析和实验测量：(1)分析了空间自由电荷产生及其在固相、液相和相界面的输运机制，提出了基于欧姆和非欧姆固体的固液两相电流体区别模型，导出了电场力驱动对流及固相萃取两种机制的数学模型，给出无流动状态下的电场和电荷密度分布解析解；(2)引入了线性稳定性分析方法，分析液相区流动不稳定性和高频振荡现象，获取不同模型内电场强化对流失稳的线性，创新性的提出了采用线性格子Boltzmann方法作为一种新工具进行全局稳定性分析；(3)建立基于介观格子Boltzmann方法的数值模型，给出从二维平板到三维复杂形状、多种电荷下的模拟结果，并搭建了数值仿真平台，实现一系列电流体问题的二阶精度求解；(4)发展有效的实验手段，验证电场强化传热效果并探索强化传热优化方案。该研究将建立起电场强化固液相变问题有效的理论分析方案、数值模拟平台及实验数据库，为基于电场的强化传热传质创新应用提供技术支撑。