单一尺度的多孔表面由于无法平衡沸腾中蒸汽的溢出及液体吸入对尺度的不同要求，导致严重的热力学非平衡：启动过温、流动和传热不稳定性及临界热流密度等。本项目提出采用多尺度微细结构表面抑制热力学非平衡性。对符合沸腾传热气泡动力学原理的多尺度结构进行构建、表征、及拓扑优化设计。研究多尺度结构表面池沸腾传热，及采用多尺度微细结构制备蒸发器的回路热管的传热特性。重点研究并揭示多尺度微细结构减小沸腾起始点温度、抑制流动与传热不稳定性、提高临界热流密度等的规律及机理。研究多尺度微细结构沸腾传热中蒸汽溢出通道尺度与多孔颗粒尺度及孔隙尺度的匹配。基于非平衡热力学，分区建立多孔区及蒸汽溢出区，包含汽泡核化和长大、蒸汽溢出、及液体吸入的数学模型并运用基于格子Boltzmann的耦合多尺度有限容积法进行数值模拟。实验与理论相互验证,以揭示多尺度表面强化沸腾换热的机理。

Porous surfaces with uniform pore size can not satisfy the requirements for different scales for steam release and liquid suction, leading to a severe thermodynamic non-equilibrium to cause temperature excursion, flow and heat transfer instability and critical heat flux, etc. The multi-scale porous surfaces will be constructed, characterized and designed based on the topological optimization, which are consistent with the bubble dynamics principle for bubble release and liquid suction. They will be used as the enhanced surfaces for pool boiling experiments and evaporator surfaces for heat pipe experiments. The studies will be focused on the mechanisms of the reduction of the temperature at the onset of nuclear boiling, suppression of the flow and heat transfer, and increase of boiling critical heat fluxes. The studies will identify the match principle among the porous particle size, pore size, capillary size for vapor release and liquid suction. The mathematical model will be proposed in the porous regions in which bubble nucleation, growth and liquid suction takes place and vapor release regions respectively, based on the non-equilibrium thermodynamics. The Lattice Boltzmann method will be coupled with the finite volume analysis to perform the numerical simulation. The theory and experimental results will be validated mutually. The studies will identify the heat transfer enhancement mechanism using the multi-scale porous surface.