火箭推进

针对火箭飞行工作中高空发动机燃料主管路系统防热罩存在热防护能力不足的问题,开展了高空羽流条件下的仿真计算和分析,依据温度计算值确定了防热罩紧固件在高温下抗拉伸强度低,在较高拧紧力矩条件下存在锌、镉脆断裂的薄弱环节,从而导致防热罩脱落。防热罩脱落后其内充填的隔热包覆材料被羽流吹落,燃料主汽蚀管连接法兰直接暴露在高温羽流环境中,高温导致法兰连接及密封失效从而产生燃料泄漏。针对防热罩热防护设计中存在的薄弱环节完成了设计改进,采用头锥形防热罩、高温合金材料的紧固件和多层耐高温隔热材料捆扎包覆等设计改进方案后,经过了高温、振动、地面发动机热试车和飞行试验验证,未出现前述故障。

For the problem of insufficient thermal protection capability of the heat shield of the main fuel pipeline in high altitude engine during the flight, simulation calculation and analysis under high-altitude plume conditions were carried out.Based on the calculated temperature, it is determined that the heat shield fastener has low tensile strength at high temperatures, and there are weaknesses of Zn-Cr brittle fracture under the condition of high tightening torque, which leads to the fall off of the heat shield.After the heat shield falls off, the insulation material inside the heat shield is blown off by the plume flow, and the connecting flange of main fuel venturi-tube is directly exposed to the high temperature plume environment, which leads to the failure of flange and seal, resulting in the fuel leakage.To improve the design of the heat shield, the cone-shaped heat shield, fastener of high temperature alloy material and multi-layer of high-temperature heat-resistant insulation material are adopted.These optimizations have been validated by the high temperature, vibration, ground and rocket flight tests.

引言
1 防热罩工作环境温度计算及故障机理分析
2 防热罩结构改进方案
3 试验验证
4 结语

图1 高空发动机燃料主管路防热罩<br/>Fig.1 Heat shield of main fuel pipeline in high altitude engine

图1 高空发动机燃料主管路防热罩
Fig.1 Heat shield of main fuel pipeline in high altitude engine

图2 高空羽流热环境防热罩计算模型<br/>Fig.2 Simulation model of heat shield in high temperature plume flow

图2 高空羽流热环境防热罩计算模型
Fig.2 Simulation model of heat shield in high temperature plume flow

图3 防热罩外表面温度随火箭飞行时间变化曲线<br/>Fig.3 Out-surface temperature of heat shield during rocket flight

图3 防热罩外表面温度随火箭飞行时间变化曲线
Fig.3 Out-surface temperature of heat shield during rocket flight

图4 稳态条件下防热罩温度场<br/>Fig.4 Temperature field of heat shield under steady state condition

图4 稳态条件下防热罩温度场
Fig.4 Temperature field of heat shield under steady state condition

图5 改进前防热罩上端平面盖片<br/>Fig.5 Upper flat sheet of heat shield before improvement

图5 改进前防热罩上端平面盖片
Fig.5 Upper flat sheet of heat shield before improvement

图6 改进后防热罩上端锥面盖片<br/>Fig.6 Upper cone sheet of heat shield after improvement

图6 改进后防热罩上端锥面盖片
Fig.6 Upper cone sheet of heat shield after improvement

图7 防热罩紧固件高温试验装置<br/>Fig.7 High temperature test equipment of heat shield fasteners

图7 防热罩紧固件高温试验装置
Fig.7 High temperature test equipment of heat shield fasteners

图8 断口金相检查结果<br/>Fig.8 Metallographic examination results of the section

图8 断口金相检查结果
Fig.8 Metallographic examination results of the section

[1] 郭敬, 孔凡超, 胡旭坤.空间发动机羽流研究技术发展综述[J].火箭推进, 2014, 40(6):51-58.

备注

引言

1 防热罩工作环境温度计算及故障机理分析

2 防热罩结构改进方案

3 试验验证

4 结语

期刊信息