基于热非平衡模型的非均匀热流相变发汗冷却数值研究

Numerical investigation of phase-change transpiration cooling under non-uniform thermal flux utilizing local thermal non-equilibrium Model

中文关键词: 多孔介质  相变发汗冷却  局部热非平衡  非均匀热流边界

英文关键词: porous medium  phase-change transpiration cooling  local thermal non-equilibrium  non-uniform heat flux boundary

中文摘要:

      多孔介质相变发汗冷却是应对飞行器关键热部件极端散热需求的有效手段，相变发汗过程中流体与多孔固体间存在明显温差，考虑流-固间对流传热可更为准确地预测多孔介质内气液相变传热过程。本文采用局部热非平衡模型结合两相混合模型，开展了非均匀热流边界下多孔介质内相变发汗冷却数值模拟。结果表明，强非线性热流影响下冷却剂会率先在高热流区域发生相变，形成蒸汽堵塞，从而引发传热恶化，多孔板最高温度远高于均匀热流边界下的温度值。因此合理调控多孔板孔隙率分布，可有效避免蒸汽堵塞，缓解此类传热恶化现象，实现飞行器关键热部件多孔发汗冷却结构的高效热防护。

英文摘要:

      Phase-change transpiration cooling in porous media is one of the effective methods for addressing the extreme heat dissipation requirements of critical thermal components in spacecraft. During the phase-change process, the obvious temperature differences exist between the fluid and porous solid. Considering the convective heat transfer between fluid and solid can predict the phase-change heat transfer process within porous medium more accurately. In this study, a local thermal non-equilibrium model is utilized combined with a two-phase mixture model to conduct the numerical simulations of phase-change transpiration cooling under nonlinear heat flux boundaries. The results show that the coolant initially undergoes phase change in high heat flux regions, leading to steam blockage and subsequently deteriorating the heat transfer. The highest temperature of porous plate is significantly higher than that under uniform heat flux boundaries. Therefore, optimizing the porosity layout of porous plate can effectively prevent the steam blockage and mitigate the heat transfer deterioration, achieving efficient thermal protection for the critical thermal components with porous transpiration cooling structures.