纤维增强复合材料以其耐高温、抗氧化的优点，在航空航天、可再生能源中具有巨大的优势与发展潜力。但由于其组分、结构和功能的复杂性，使其在使用过程中的可靠性难以保证，因此研制安全可靠的多元高温、长时抗氧化、轻质异形构件，能够提高材料的安全防护能力，是当前的迫切需求。本文通过理论分析-模型设计-装配建造-模拟优化的研究思路，首先分析发生在反应器内部的物理过程，并据此建立数学物理方程，确定相应的参数。根据实验需求先后设计和搭建卧式和立式双温区-双通道化学气相渗透/沉积炉。对卧式炉进行等温化学气相渗透实验，验证了卧式炉制备隔热防火复合材料的可行性，进一步地在此基础上探究温度、温度梯度、气体速度浓度对致密化过程的影响趋势。接下来根据参数影响进行两步法化学气相渗透/沉积实验，验证了沉积均匀性。最后通过设计碳纤维/金属夹层结构复合材料，分析在立式炉中进行化学气相渗透/沉积过程中，加热器、夹心结构及芯/板比对材料性能的影响，并据此研究夹层结构复合材料的轴向和径向温度分布以及增密过程中的增密效率。综合实验与模拟结果来看，卧式炉在1123 K到1223 K之间预制体的开孔隙率呈现先下降后上升的趋势，密度则相反；在1173 K至1198 K之间存在一个最佳温度，在该温度下致密化效果最好。高温影响反应速率，低温影响沉积均匀性，速度、浓度和温度梯度共同耦合作用影响致密化效率。因此在实验过程中必须进行调节参数匹配实现高效均一的致密化。除了实验条件参数外，隔热防火材料的结构和成分设计也是重点关注的特征。实验设计了碳纤维为面板，金属格栅为夹层的碳/金属夹层结构复合材料，根据芯材的分布和芯/板比的影响趋势，当夹层/面板比在低于0.03时，达姆克勒数较小，温度梯度和反应速率都比基准情况下提高了70%，实现径向温度均匀与轴向温度梯度。
Fiber-reinforced composites offer significant advantages in aerospace and renewable energy due to their high temperature and oxidation resistance. The complexity of their components, structures, and functions makes reliability during use difficult to ensure. Therefore, the urgent need for safe and reliable lightweight components that can withstand multi-temperature, long-term oxidation is evident. These advancements aim to improve material safety and protection.This paper follows a research framework that includes theoretical analysis, model design, assembly and construction, and simulation optimization. The research begins with an analysis of the physical processes inside the reactor and the establishment of corresponding mathematical-physical equations. Subsequently, horizontal and vertical dual-temperature zone and dual-channel chemical vapor infiltration/deposition furnaces are designed and constructed to meet experimental requirements. Isothermal chemical vapor infiltration (ICVI) experiments are conducted on the horizontal furnace to validate its feasibility for producing heat-insulating and fire-retardant composites. The effects of temperature, temperature gradient, and gas velocity concentration on the densification process are further investigated based on the ICVI experiments. Two-step chemical vapor infiltration/deposition experiments are then performed to ensure deposition uniformity based on parameter influence. Finally, the effects of heater, sandwich structure, and core/plate ratio on the material properties during the chemical vapor phase infiltration/deposition process in a vertical furnace are analyzed using carbon fiber/metal sandwich structure composites. The axial and radial temperature distributions of the sandwich structure composites as well as the densification efficiency during the densification process are investigated. The combined experimental and simulation results show that the open porosity of the prefabricated body of the horizontal furnace between 1 123 K and 1 223 K shows a decreasing and then increasing trend, while the density is the opposite; there exists an optimal temperature between 1 173 K and 1 198 K, at which the densification effect is the best. The high temperature affects the reaction rate, the low temperature affects the deposition uniformity, and the combined coupling of velocity, concentration and temperature gradient affects the densification efficiency. Therefore, the parameters must be adjusted during the experiment to achieve efficient and uniform densification.In addition to experimental condition parameters, the structural and compositional design of insulation and fireproofing materials is a critical focus. Experimental design was used to create carbon/metal sandwich structure composites with carbon fiber panels and a metal grill interlayer. When the interlayer/panel ratio is below 0.03, the Damocles number is small, leading to a 70% increase in temperature gradient and reaction rate compared to the base case. This achieves radial temperature homogeneity and the desired axial temperature gradient.
