RBCC发动机火箭出口结构热防护研究

Thermal Protection of Rocket Exit Structure in RBCC Engine

关键词:  RBCC发动机  火箭  出口结构  热防护  试验

Key words:  RBCC engine  Rocket  Outlet structure  Thermal protection  Experiment

摘要:

基于目前RBCC组合发动机开展了火箭出口位置结构热防护的研究，该发动机结构形式为火箭从冲压发动机燃烧室侧壁嵌入，火箭出口紧贴冲压发动机燃烧室壁面。火箭出口超高温、高热流、冲刷大的特点，导致该位置热环境非常严酷，为了探索火箭出口位置热防护结构，开展了三种结构热防护方案的试验研究。研究结果表明，石英/酚醛内壳和高温合金外壳复合结构热防护方案能够满足30s量级的地面试验，能够满足火箭出口恶劣环境的热防护要求。研究结果还表明，热防护材料至关重要，高温合金材料不适合应用于火箭出口热防护；高硅氧/酚醛材料虽然基本能满足试验的热防护需求，但其抗烧蚀性能略低，尤其当材料完全炭化后产生的强度降低、收缩、分层、热导系数增加等问题，在更长时间试验中会导致热防护失效，针对这些问题，本文提出了进一步研究建议。

Abstract:

Based on the current research on the thermal protection of the rocket exit position structure of a certain RBCC combined engine， the structure of the engine is that the rocket is embedded from the side wall of the ramjet， and the rocket outlet is close to the wall of the ramjet combustion chamber. The characteristics of ultra-high temperature， high heat flow， and large erosion at the rocket exit lead to very harsh hot environment. In order to explore the location of the rocket exit， experimental research of three thermal protection schemes has been carried out. The results show that the thermal protection scheme of the composite structure of the quartz-phenolic inner shell and the superalloy outer shell can meet the ground test of the order of 30s， and it was finally verified in the flight test. The results also show that thermal protection materials are very important， and superalloy materials are not suitable for rocket exit thermal protection. Although high silicon oxide/phenolic materials can basically meet the thermal protection requirements of the test， their ablation resistance is slightly lower， especially when the material is completely carbonized， facing the problems of strength reduction， shrinkage， stratification， and increase in thermal protection failure in longer tests. In view of these problems， further research suggestions are put forward.