井下火箭发射燃气对消音层冲蚀损伤模型及特性

井下火箭发射过程中消音层在发动机高温、高速燃气流作用下存在冲蚀损伤，会影响火箭发射安全，系统分析消音层燃气冲蚀损伤特性，对消音层的后期修复以及地下井结构优化具有重要意义。消音层冲蚀损伤是复杂的热-流体-固体多场耦合问题，以典型玻璃丝棉消音层为例，建立玻璃丝棉相变传热和烧蚀损伤数学模型；基于燃气流场数据提取与预处理、插值程序编写和有限元分析软件Abaqus用户子程序开发，搭建消音层燃气冲蚀损伤仿真平台，采用子模型技术，建立玻璃丝棉烧蚀数值仿真模型；对玻璃丝绵烧蚀过程进行仿真，并分析地下井井筒直径、燃气射流初始冲击高度及发动机建压速率3个因素对玻璃丝棉烧蚀损伤的影响；通过玻璃丝棉原理性冲蚀试验对数值仿真模型进行验证。结果表明：玻璃丝棉普遍发生烧蚀，且主要发生在回流和失稳阶段，沿地下井周向分布差异较小，沿轴向越靠近底部烧蚀越严重；减小井筒直径或增大建压速率将加剧烧蚀，增大冲击高度会减少烧蚀；试验结果显示玻璃丝棉都有一定的烧蚀，证明建立的仿真模型是正确的。

Model and Characteristics of Jet Flow Erosion Damage to Silencer Layer in Silo Launching Process of Rocket

The silencer layer is corrosively damaged by high temperature and high speed jet flow of rocket engine in the launching process. This affects the launching safety.The analysis of jet flow erosion damage is important to the late repair of silencer layer and the optimization of silo structure. The jet flow erosion damage to the silo silencer layer is a complicated thermal-hydro-mechanical coupling problem. The typical glass wool silencer layer is researched to build the phase change heat transfer and jet flow erosion damage mathematic models. A simulation platform of jet flow erosion damage is established by extracting and pretreating the jet flow field data, writing an interpolation program and developing Abaqus user subroutine. And a sub-model method is introduced to build a glass wool numerical simulation model. The ablation process of glass wool was simulated, the ablation damage was analyzed under the effects of silo diameter, initial height of jet flow and engine pressure build-up speed, and the simulation and ablation damage principle experiment for silo silencer layer were performed. The simulated results show that the glass wool silencer layer of the silo is generally damaged during jet flow ablation, which mainly occurs in the reverse flow and destabilizing stage. And the ablation damage is similar in the circumferential direction of the silo, but different in the axial direction. In addition, the damage is more serious closer to the bottom of silo, and the decreased diameter of silo or the increased pressure build-up speed of engine would aggravate ablation. But the increased initial height of jet flow will weaken ablation. The experimental results show that the glass wools are all damaged to a certain extent.