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开展了针刺预制体分层对吸气式发动机燃烧室C/C-SiC热防护性能影响的实验研究。分析了针刺预制体制作过程中出现预制体分层的原因,指出缠绕张力大小是导致制体分层的因素。通过比较有分层和无分层两种情况的实验结果,发现预制体局部存在的分层,造成了C/C-SiC热防护结构在热防护实验中出现结构破坏,说明由于预制体分层会引起C/C-SiC热防护结构存在局部层间结合力弱以及局部区域存在SiC基体聚集区,从而严重影响C/C-SiC热防护的结构完整性。为了避免出现针刺预制体分层,提出了在预制体制作过程中控制环向纤维缠绕张力的大小和均匀性,并在其完成初步致密化后进行CT检测,发现可能存在的分层,并指出预制体密度大小与预制体是否存在分层有一定的关联性,应通过实验结果和检测结果的统计分析,确定合理的预制体密度大小范围。提出从宏观上预制体密度指标作为评定预制体是否存在分层的判据。
The experimental research on the influence of acupuncture prefabricated layer on the thermal protection performance of C / C-SiC combustion chamber was carried out. The reasons for preform delamination during the manufacture of acupuncture preform were analyzed. It was pointed out that the winding tension was the factor that caused the delamination. By comparing the experimental results with both stratified and non-stratified conditions, it is found that the delamination exists locally in the preform, resulting in the structural failure of the C / C-SiC thermal protection structure in the thermal protection experiment, indicating that due to the pre-stratification C / C-SiC thermal protection structure will lead to the existence of local layer bonding weakness and the presence of local SiC matrix aggregation zone, thus seriously affecting the structural integrity of C / C-SiC thermal protection. In order to avoid delamination of acupuncture preform, we proposed the control of the size and uniformity of the winding tension of the loop fiber in the process of preform production. CT examination was conducted after the initial densification, and possible stratification was found. It is pointed out that there is a certain correlation between the density of preform and the existence of preform, and the range of reasonable preform density should be determined through the statistical analysis of experimental results and test results. It is proposed that macroscopically the prefabricated bulk density index is used as a criterion to evaluate the existence of delamination in the preform.