The XYZ 3-dimensional thermal conductivities of the C/C up to 2000 °C were measured by a laser flash method. Carbon fiber-reinforced carbon composites (C/C) were generally developed for aerospace missions due to their excellent thermal resistivity at ultrahigh temperature. C/C must endure harsh environments such as thousands of degrees Celsius without degradation of its mechanical properties. To solve this problem, among the passive thermal protection system, we suggest a method of conducting more heat through the mono-axial direction, which resulted in ease of the thermal rise in the heat receiving part. For example, the X-43A flight applied unbalanced C/C (UCC) with different carbon fiber orientation ratios according to the XY direction in the leading edge part. To investigate the difference in thermal conductivity between unbalanced C/C (UCC) and balanced C/C (BCC), unbalanced and balanced preforms were prepared by a needle punching process, and then they were densified by pitch infiltration and a carbonization process. We compared and analyzed the effects of unbalanced C/C(UCC) and balanced C/C (BCC) structures on the thermal conductivity. We also designed the “rule of mixtures” equation for calculating thermal conductivities of each C/C using reported data of carbon fiber and graphite matrix. Our calculations of thermal conductivity ratio match the ratio of real data.

通过激光闪光法测量直至2000℃的C / C的XYZ 3维热导率。碳纤维增强碳复合材料（C / C）通常在超高温下具有出色的耐热性，因此通常用于航空航天领域。C / C必须承受恶劣的环境，例如数千摄氏度，而不会降低其机械性能。为了解决这个问题，在被动式热保护系统中，我们建议一种通过单轴方向传导更多热量的方法，从而使受热部分的热量容易升高。例如，X-43A飞行器根据XY应用了具有不同碳纤维取向比的不平衡C / C（UCC）前端部分的方向。为了研究不平衡C / C（UCC）和平衡C / C（BCC）之间的热导率差异，通过针刺工艺制备了不平衡和平衡的预成型坯，然后通过沥青浸渗和碳化工艺对其进行了致密化。我们比较并分析了不平衡C / C（UCC）和平衡C / C（BCC）结构对热导率的影响。我们还设计了“混合规则”公式，使用碳纤维和石墨基体的报告数据来计算每个C / C的热导率。我们计算的导热系数与实际数据的比例相匹配。