含相变的多孔介质中汽液两相流动与传热的LBM研究

项目名称： 含相变的多孔介质中汽液两相流动与传热的LBM研究

项目编号： No.11472269

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 黄海波

作者单位： 中国科学技术大学

项目金额： 86万元

中文摘要： 本项目拟开展含相变（蒸发、沸腾、凝结）的多孔介质中汽液两相流动和传热的格子玻尔兹曼方法(LBM)数值模拟研究，探讨此类复杂流动与传热问题的微观机理。研究内容主要包括：基于理论分析，进一步发展含相变的热LBM两相模型，提高其模拟多孔介质中两相流的精度及稳定性；通过三维LBM大规模并行计算，研究多孔介质中孔隙结构、润湿性、重力和温度对蒸发的影响；针对燃料电池大电流工况下，气体扩散层(GDL)疏水性质（润湿性）及温度发生改变的情况，研究GDL中水分动态分布规律；对于多孔介质中的沸腾问题，考察孔隙结构及导热系数的影响；研究毫米级不同孔隙结构的多孔介质加热面上容积沸腾时强化传热的机理。通过以上微观模拟建立相应宏观预测模型。本项应用基础研究具有重要学术价值，研究成果对土壤水分管理、提高燃料电池效率及寿命、提高地热利用率及提高沸腾强化传热效率等具有技术价值，可为能源化工及农业部门提供重要的理论依据。

中文关键词： 多孔介质；多相流；相变；传热传质；格子Boltzmann方法

英文摘要： Liquid-vapor flow and heat transfer including phase transition (evaporation, boiling and condensation) in porous media plays an important role in many technologies in engineering and science. In this work, we plan to apply the lattice Boltzmann method (LBM) to study these complex flows. Through LBM simulations, the micro flow and heat transfer mechanism in these flows will be explored. Specifically, the research involves following objectives. (1) Based on theoretical analysis, the thermal two-phase LBMs including phase-transition effect would be further developed. It is expected the developed method is able to improve the accuracy and the stability for simulations of such complex flows. (2) Through an extensive series of 3D parallel computational studies, the effect of the porous structure, the wetability, gravity and the temperature on the evaporation in the porous media would be identified. (3) Water management inside the gas diffusion layer (GDL), which is made with hydrophobic porous carbon fibre,is key to the performance of the fuel cell. At high current densities, the wettability of the GDL and the temperature field may change. As a result, liquid water might lead to blocked pathways in the GDL and the catalyst layers which in turn limit the maximum achievable power density. Hence, the effect of the wettability, temperature, and porous structure on liquid water distribution will be investigated intensively.(4) For geothermal systems, the porous structure and thermal conductivity of the rock may affect the boiling and the movement of the liquid-vapor interface, we would try to explore the relevant mechanism. Micro-cavity in a structured superheated surface may significantly enhance the pool boiling. The mechanism about how different shapes of pores in mm scale enhance boiling heat transfer would be investigated.This proposed research is of great academic interest. It also shed some light on the management and control of the water in soil, the performance enhancement of the fuel cell, improvement of the geothermal system and the boiling heat transfer enhancement. It may provide theoretical bases for the energy, chemical and algriculture departments.

英文关键词： porous media;multiphase flow;phase transition;heat and mass transfer;lattice Boltzmann