摘要
固体火箭发动机实验条件下,对4D编织C/C复合材料变参数流道拉瓦尔喷管进行了烧蚀特性研究。针对变流道喷管变化的烧蚀角度,分析了材料的烧蚀机理。结果表明,由于变流道的原因,从收敛段到喉部烧蚀逐渐加剧,在收敛段与喉部过渡段45°烧蚀角出烧蚀最为严重,烧蚀角越大,烧蚀越严重。之后,烧蚀程度明显逐渐减小。烧蚀率沿着变流道喷管轴向逐渐改变,最大烧蚀率是0.056 mm/s,最大质量烧蚀率是0.157 kg/m^2·s。并且,轴向纤维、径向纤维到环向纤维,烧蚀尖角逐渐增大。烧蚀特性与粒子速度、粒子撞击角度、粒子浓度、壁面剪切力等因素相关。在热化学烧蚀和机械剥蚀共同作用下,变流道是不同烧蚀行为的主要影响因素。
Ablation of a 4D-braided C/C composite fabricated with axial rods in the parameter-variable channel of a Laval nozzle（or a convergent-divergent nozzle,a tube that is pinched in the middle） was performed in the experimental conditions of a solid rocket motor. Gas-solid flow and erosion were also simulated with the discrete phase model. The ablation of the composite was caused by thermochemical and mechanical erosion and was analyzed based on the morphology of different sections of the channel in the nozzle with different angles between the gas flow direction and the surface of the composite （ ablation angle） . Results showed that the ablation behavior was related to the velocity, concentration, collision angle to the surface and the wall shear force of parti-cles in the ablation gas. The ablation gradually increased with the rate of gas flow and was a maximum at the maximum ablation an-gle of 45° in the compression section. In the expansion section,beyond the throat,ablation decreased significantly. The maximum linear and mass ablation rates were 0. 056 mm/s and 0.157 kg/m2.s, respectively. The carbon fibers formed a tapered tip,whose sharpness depended on the ablation angle and the braiding direction.
出处
《新型炭材料》
SCIE
EI
CAS
CSCD
北大核心
2017年第4期365-373,共9页
New Carbon Materials
基金
National Natural Science Foundation of China(51005179)~~
