火箭推进

为了探究供应管路夹气对液体火箭发动机启动过程的影响,利用彩色高速相机捕捉了双组元150 N发动机直流互击式喷注器雾化特征,对比了夹气和不夹气状态下喷雾场的启动过程,并在高空模拟热试车台进行了国内首次小推力空间液体火箭发动机夹气启动验证试验,采用氮气对真空舱内推进剂供应管路吹除后直接进行推进剂充填并点火。结果表明,夹气状态下的喷注器喷雾场空间分布上主要集中于中心轴线区域,局部区域雾化效果增强,液滴直径减小,雾化锥角增大; 夹气雾化充分发展时,中心主射流起始段和边区射流局部出现断流,空间整体分布均匀性较差。高空模拟热试车条件下,夹气没有对发动机启动过程造成持续性振荡,点火推力峰有增大的趋势,发动机其他性能、温度、振动等测量参数以及开关机过程没有发生显著变化。但是,夹气一定程度上增加了发动机启动过程的复杂性和不确定性因素,工程上需要引起足够重视,强烈建议热试车时增加3 s预点火程序,排出推进剂充填后发动机控制阀前可能产生的气泡,确认发动机启动无异常后再继续后续点火程序。

In order to explore the effect of gas entrainment in the supply pipelines during the liquid rocket engine start-up process,the atomization characteristics of 150 N bipropellant engine impinging injector were captured by the color high-speed camera.The start-up processes of spray field under the gas-entrained and non-gas-entrained states were compared.The first domestic verification test of low-thrust space liquid rocket engine start-up with entrained gas was carried out in the high altitude simulation hot fire test bench.The propellant supply pipelines in the vacuum cabin were directly filled after nitrogen blowing,and then the engine was ignited.The results show that the injector spray field distribution with gas entrainment is mainly concentrated in the central axis area,and the local area atomization effect is enhanced.In addition,the droplet diameter decreases and the atomization cone angle increases.When the atomization with gas entrainment is fully developed,the initial section of the central main jet and the side jets will be locally cut off,and the overall distribution uniformity of the injector spray field is poor.Under the hot fire test conditions,there is no continuous oscillation during the engine start-up process due to the gas entrainment,the engine ignition thrust peak tends to increase,and other measurement parameters including performance,temperature,vibration and start-up and shutdown process of the engine do not change significantly.However,the gas entrainment may increase the complexity and uncertainly of the engine start-up process,and enough attention needs to be paid in engineering application.It's strongly recommended to add a 3-second pre-ignition program during the hot fire test to discharge the bubbles before the control valves after propellant filling,and to continue the subsequent ignition procedure of the engine after confirming that there is no abnormality during the start-up process.

引言
1 试验系统与试验方法
2 冷流试验结果与分析
3 高空模拟热试车验证
4 讨论
5 结论

图1 冷流试验系统<br/>Fig.1 Sketch of experiment setup

图1 冷流试验系统
Fig.1 Sketch of experiment setup

表1 150 N发动机主要设计参数<br/>Tab.1 Design parameters of 150 N engine

表1 150 N发动机主要设计参数
Tab.1 Design parameters of 150 N engine

图2 夹气与不夹气时喷注器喷雾场对比<br/>Fig.2 Comparison of injector spray field with and without gas entrainment

图2 夹气与不夹气时喷注器喷雾场对比
Fig.2 Comparison of injector spray field with and without gas entrainment

图3 夹气状态喷雾场后续变化情况<br/>Fig.3 Subsequent change of spray field with gas entrainment

图3 夹气状态喷雾场后续变化情况
Fig.3 Subsequent change of spray field with gas entrainment

图4 发动机高空模拟热试车状态<br/>Fig.4 Engine state in the high altitude simulation hot fire test bench

图4 发动机高空模拟热试车状态
Fig.4 Engine state in the high altitude simulation hot fire test bench

图5 不夹气时发动机性能和温度曲线<br/>Fig.5 Distribution of engine performance and temperature without gas entrainment

图5 不夹气时发动机性能和温度曲线
Fig.5 Distribution of engine performance and temperature without gas entrainment

图6 夹气时发动机性能和温度曲线<br/>Fig.6 Distribution of engine performance and temperature with gas entrainment

图6 夹气时发动机性能和温度曲线
Fig.6 Distribution of engine performance and temperature with gas entrainment

图7 发动机烧蚀形貌<br/>Fig.7 Ablated engine appearance

图7 发动机烧蚀形貌
Fig.7 Ablated engine appearance

图8 发动机性能和温度曲线<br/>Fig.8 Distribution of ablated engine performance and temperature

图8 发动机性能和温度曲线
Fig.8 Distribution of ablated engine performance and temperature

图9 喷注器法兰振动曲线<br/>Fig.9 Vibration distribution of injector flange

图9 喷注器法兰振动曲线
Fig.9 Vibration distribution of injector flange

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备注

引言

1 试验系统与试验方法

2 冷流试验结果与分析

3 高空模拟热试车验证

4 讨论

5 结论

期刊信息