非平衡气动加热条件下的材料热响应差异研究

针对风洞烧蚀试验中碳/碳与超高温陶瓷两种复合材料存在热响应差异的问题,本文从材料壁面催化与非平衡流场气动加热的机理出发,基于两种风洞设备设计了3个烧蚀试验状态,并对可能影响材料热响应的重要因素进行了分析.结果表明:在不同试验设备条件下,碳/碳端头驻点温度差异主要是由试验状态调试偏差和温度测量偏差造成的,而超高温陶瓷端头驻点温度的差异主要是由不同条件气流非平衡度不同、试件表面实际接受的热流不同造成;对碳/碳材料而言,由于其壁面催化特性接近完全催化壁面,在试验设备选择或状态调试时,可以不必考虑流场非平衡度的影响;而对于超高温陶瓷材料,在试验设备的选择上,则需要结合风洞非平衡流场特点,对试验考核的有效性做充分评估.相关结论可为碳/碳、超高温陶瓷复合材料防热性能的考核与评价提供参考与借鉴.

The difference in the thermal response under non-equilibrium aerodynamic heat

In this paper, considering the difference of the thermal responses between C/C and ultra high temperature ceremics (UHTC) in wind tunnel ablation tests, three conditions based on two heating facilities have been designed, and the important factors influencing the thermal responses have also been analyzed from the viewpoint of materials surface catalytic and non-equilibrium flow field aerodynamic heat. The results indicated that, the difference in the stagnation temperature of C/C ends using the different testing facilities is mainly caused by the debugging deviation and temperature measurement deviation under testing conditions, whereas the difference in the stagnation temperature of UHTC ends is mainly attributed to the different in the non-equilibrium degree and the actual surface heat flow. When selecting the testing facilities, non-equilibrium degree of the flow field needs not to be considered due to the fact that C/C surface catalytic properties are close to fully catalytic one, whereas, for UHTC, the non-equilibrium flow field should be considered to fully assess the validity of the testings. The results obtained in this work can shed more insights on the assessment and evaluation of the thermal protection performance for the C/C, and UHTC composites.