Abstract: With the advantage of simple process and low cost, high silica phenolic composite has been used as SRM thermal protection material. In order to investigate its application in ramjet thermal protection, heat-resistant layer of high silica phenolic composites in large scale ramjet chamber has been designed and experimental studied. The results show that high silica phenolic composites is adaptive to work properly up to 300 seconds in the harsh environment of ramjet chamber. Due to non-uniform temperature distribution of ramjet chamber, phenolic carbonization is non-synchronous with high silica fiber fusion, and crack and delamination of heat-resistant layer of high silica phenolic composites after working longer time(＞300s) can occure.High silica phenolic composites form and performance changes greatly after pyrolysis and carbonization. For these problems, proposals are made and measures are suggested. This research is valuabe for simplifing process and reducing cost of the thermal structure in ramjet chamber.

Key words: Ramjet engine;Combustion chamber；Thermal protection; Experimental investigation

摘要： 高硅氧/酚醛树脂基复合材料具有成型工艺简单和成本低的特点,被广泛地应作固体火箭发动机的防热材料。为了探索高硅氧/酚醛树脂基复合材料应用于冲压发动机燃烧室被动热防护结构,对高硅氧/酚醛树脂基复合材料大尺度冲压发动机燃烧室热防护层进行了实验研究。研究结果表明,冲压发动机燃烧室热防护层能工作到300s,高硅氧/酚醛热防护层能够适应其恶劣的工作环境要求。同时,通过实验研究也表明,更长工作时间之后,由于冲压发动机燃烧室工作温度的不均匀,导致酚醛树脂基体的分解与增强的高硅氧纤维熔融不同步,且热解、碳化后的形态和性能都会发生较大的变化,由此会导致其尺寸收缩、力学性能降低、导热系数增加,更长时间工作容易产生裂纹、分层等问题。针对这些问题,提出了进一步研究的建议。本项研究对于发展成型工艺简单和成本低的冲压发动机燃烧室热防护结构具有重要的价值。

关键词: 冲压喷气发动机;燃烧室;热防护;试验研究