半潜入喷管收敛段碳/酚醛材料烧蚀特性

Ablation characteristics of carbon/phenolic at converging section in semi-submerged nozzle

采用流固热耦合数值方法,以及Abaqus的ALE(arbitrary Lagrangian-Eulerian,任意拉格朗日欧拉方法)自适应网格技术,对位于半潜入喷管收敛段的碳/酚醛的烧蚀现象进行了预估,与试验结果进行了对比分析。结果表明:在收敛段,Al/A_(l2)O_(3)液滴或颗粒对材料的传热烧蚀起到了关键作用,当气流与材料表面平行时,液滴或颗粒的影响很小;从碳/酚醛热分解角度出发,基于完全碳化即被剥蚀的假设,基本能够预估碳/酚醛材料的烧蚀特征,烧蚀速率大约为0.3 mm/s;后效碳化对材料碳化过程的影响明显,发动机工作期间,分解层的厚度大约为2.0 mm,考虑后效作用,分解层厚度可能会增加至4.0 mm左右;与喉衬接触的材料区域,喉衬的传热会明显加剧材料的碳化过程。

By solid-gas heat coupled numerical method and the ALE(arbitrary Lagrangian-Eulerian)adaptive meshing technique,the ablation of carbon/phenolic at the converging section in semi-submerged nozzle was investigated,and the results were validated by comparing the re-sults with the experiment data.The results showed that the Al/A_(l2)O_(3) particles and droplets had great effect on the heat transfer and ablation process at the converging section.The effects of Al/A_(l2)O_(3) on the ablation can be ignored when the gas traveled almost parallel to the surface.Based on the decomposition mechanism of phenolic,the ablation characteristics of carbon/phenolic can be predicted assuming that the fully charred material was ablated immediately,and the ablation rate was about 0.3 mm/s.The char formation process after the motor burnout was very important for the carbon/phenolic.The thickness of pyrolysis zone was about 2.0 mm during the operating process of the motor,and may increase to 4.0 mm considering the pyrolysis process after motor burnout.The ablation of carbon/phenolic in contact with the carbon/carbon throat can be en-hanced owing to the heat flux through carbon/carbon throat heat transfer.