Lv Yumei, He Fei, Ding Rui, Wu Nan, Liu Taolue, Wang Jianhua
CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Hefei 230027, China.
Northwest Institute of Nuclear Technology, Xi'an 710024, China.
ACS Appl Mater Interfaces. 2022 Aug 24;14(33):38185-38195. doi: 10.1021/acsami.2c09891. Epub 2022 Aug 13.
The heat insulation ability and thermal stability of thermal protection materials play extremely important role in the thermal protection of aero-engines under high temperature. Herein, we design the carbon-SiO-AlO (CSA) composite aerogel through thermochemical restructuring from the phenol-formaldehyde resin-SiO-AlO (PSA) composite aerogel. This thermochemical restructured aerogel not only shows better adhesion property under room temperature but also possesses higher thermal stability and desirable heat insulation ability under high temperature. Taking the PSA-0.5 composite aerogel as an example, the compressive strain-stress test unveils that it can be compressed by 66% without catastrophic collapse, which is beneficial for the adhesion with the metallic matrix. Meanwhile, the transmission electron microscopy and scanning electron microscopy images exhibit the unbroken three-dimensional structure for the CSA-0.5 composite aerogel, which confirmed the structural stability of the composite aerogel after thermochemical restructuring. The thermal cycle test indicates that the weight loss of the CSA-0.5 composite aerogel is only ca. 8%, firmly confirming its thermal stability. Importantly, the thermal conductivity of the CSA-0.5 composite aerogel ranges from 0.024 to 0.083 W m K, indicating the superior performance of heat insulation. Moreover, the numerical simulation is carried out to validate the thermal protection effect of the CSA-0.5 composite aerogel as a thermal protection layer. Together with laminated cooling, it could enhance the surface cooling effectiveness of the metallic matrix to above 0.8. Briefly, this work paves a new pathway for efficient thermal protection materials of aero-engines via the rational design of the thermochemical restructured composite aerogel under the guidance of ANSYS numerical simulations.
热防护材料的隔热能力和热稳定性在航空发动机高温热防护中起着极其重要的作用。在此，我们通过对酚醛树脂-SiO-AlO（PSA）复合气凝胶进行热化学重构，设计出了碳-SiO-AlO（CSA）复合气凝胶。这种热化学重构气凝胶不仅在室温下表现出更好的粘附性能，而且在高温下具有更高的热稳定性和理想的隔热能力。以PSA-0.5复合气凝胶为例，压缩应变-应力测试表明，它可以被压缩66%而不会发生灾难性坍塌，这有利于与金属基体的粘附。同时，透射电子显微镜和扫描电子显微镜图像显示CSA-0.5复合气凝胶具有完整的三维结构，证实了热化学重构后复合气凝胶的结构稳定性。热循环测试表明，CSA-0.5复合气凝胶的重量损失仅约为8%，有力地证实了其热稳定性。重要的是，CSA-0.5复合气凝胶的热导率在0.024至0.083 W m K之间，表明其具有优异的隔热性能。此外，还进行了数值模拟以验证CSA-0.5复合气凝胶作为热防护层的热防护效果。与层板冷却相结合，它可以将金属基体的表面冷却效率提高到0.8以上。简而言之，这项工作在ANSYS数值模拟的指导下，通过合理设计热化学重构复合气凝胶，为航空发动机高效热防护材料开辟了一条新途径。
