面向变体飞行的仿生相变发汗冷却结构:热质传递机理及模型

Bionic phase-change transpiration cooling structure for morphing flight: heat-mass transfer mechanism and modeling

  • 摘要: 新一代航天运输系统具备跨空域、宽速域、重复使用、智能飞行等技术特征,传统刚性热防护系统因形变能力有限,难以满足高温变构工况下的热防护需求。借鉴植物叶脉脉序输送路径,融合柔性材料大变形特性与微通道毛细驱动机制,提出了一种自适应-自驱动柔性相变冷却结构,实现了冷却过程的高效性和均匀性。开展了地面热考核试验,在170  kW/m2热流下,结构可将壁面温度维持在130℃,验证了自驱动发汗冷却的可行性。建立了液-气-固多相传热传质耦合分析模型,阐明了冷却通道几何参数对结构冷却效果的影响规律:相比通道直径,通道角度对结构冷却效率的影响更显著,冷却效率随角度增加而降低。重点研究了典型变构工况下结构变形与温度响应、冷却消耗量之间的关联关系,发现大变形下结构表面温度波动<5%,冷却剂流量对通道直径呈现高敏感性。该研究可为新一代变构飞行器热防护系统设计提供新的技术路径。

     

    Abstract: Next-generation space transportation systems exhibit advanced technical features, including trans-atmospheric flight, broad speed regimes, reusability, and intelligent operation. Conventional rigid thermal protection systems (TPS), however, are constrained by limited deformation capabilities, rendering them inadequate for simultaneously addressing thermal insulation and structural morphing requirements under high-temperature, large-deformation scenarios. To address this challenge, an adaptive-self-driven flexible phase-change transpiration cooling structure was proposed, inspired by the fractal transport pathways of leaf venation. This design integrates the large-strain capacity of flexible materials with capillary-driven microchannel mechanisms, achieving efficient and uniform cooling performance. Ground thermal testing under moderate heat flux conditions (170 kW/m2) demonstrated the structure’s self-driving capability and cooling efficiency, with surface temperatures maintained below 130°C, validating the feasibility of phase-change transpiration cooling. A coupled heat and mass transfer model was developed by integrating surface tension theory in microchannels with liquid-gas-solid multi-phase heat transfer mechanisms, quantifying the influence of geometric parameters (e.g., channel diameter and branching angles) on cooling effectiveness. Model predictions align well with experimental data (error <10%), providing theoretical support for the parametric design of flexible phase-change cooling structures. The correlation between structural deformation range, temperature response, and coolant consumption under representative morphing scenarios was systematically analyzed. Results showed that surface temperature fluctuations remained <5%, while coolant flow responses exhibited nonlinear characteristics, highlighting the structure’s robust dynamic regulation capacity and offering new insights for flexible TPS design. Subsequent studies will introduce spatially non-uniform heat flux distributions, leveraging the established coupling model to investigate the dynamic response mechanisms of coolant flow to heterogeneous thermal loads, further enhancing the structure’s adaptive control performance. This work provides an innovative technical pathway for thermal protection system design in next-generation morphing aerospace vehicles, enabling reliable operation in extreme high-temperature and structural deformation environments.

     

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