The dynamic thermophysical properties evolution and multi-scale heat transport mechanisms of 2.5D C/SiC composite under high-temperature air oxidation environment

• Published in: Composites. Part B, Engineering Engineering, 2023-08, Vol.263, p.110831, Article 110831
• Main Authors: Zhao, Chenwei, Tu, Zecan, Mao, Junkui
• Format: Article
• Language: English
• Subjects: 2.5D C/SiC composite; Dynamic heat transport; Dynamic thermophysical properties; High-temperature oxidation; Multi-scale thermal analysis
• ISSN: 1359-8368; 1879-1069
• DOI: 10.1016/j.compositesb.2023.110831

The variations in thermophysical properties and dynamic heat transfer mechanism of 2.5D C/SiC ceramic matrix composites (2.5D C/SiC-CMC) under a high-temperature air oxidation environment are investigated by experiments and numerical simulations. A new multi-scale thermal analysis model of 2.5D C/SiC-CMC under high-temperature oxidation is proposed to predict its equivalent thermal conductivity and analysis its multi-scale heat transport mechanisms. The multi-scale thermal analysis model is developed by blending the multi-scale asymptotic thermal analysis method and oxidation kinetics theory, which includes the micro-scale model and mesoscale model. The micro-scale model simulates the oxidation process of the carbon fibers and PyC interface through oxidation kinetics, which predicts the varying equivalent thermal conductivity of yarns with oxidation. The mesoscale model is constructed based on the experimental statistics which reflect the multi-scale structure within the 2.5D C/SiC-CMC with oxidation. The mesoscale model introduces oxidation characteristics by considering dynamic variations in yarn thermal properties. The dynamic thermophysical properties of the 2.5D C/SiC-CMC with oxidation are tested in the experimental study, which verifies that the multi-scale thermal analysis model has highlighted prediction accuracy. The results show that high-temperature oxidation causes significant variations in the dynamic thermal behavior of 2.5D C/SiC-CMC which is critical for the practical thermal protection design of 2.5D C/SiC-CMC hot components in engineering applications.