火箭推进

固空已成为制约液氢推进剂大规模安全应用的关键因素之一,但目前对于固空特性的了解仍有待深入。采用数值模拟和低温可视化实验来探究液氢固空的氧氮分布规律和生长特性。结果表明,相场模型可以准确模拟纯扩散和强制对流工况下的固空生长及二次分枝过程。多晶核竞争生长时,固空会相互融合形成多晶共生体,二次枝晶还会增加融合点数量,而强制对流增加了液氢固空的危险性,富氧含量最高可达到53.3%。低温可视化实验装置能够有效观测液氢固空的全周期生长过程,当模拟气中的氧浓度为15%时,固空中的氧相对浓度可达到33.8%,证明了固空的氧富集特性。研究结果可为液氢推进剂安全使用体系的构建提供支撑。

Solid air has become one of the key factors restricting the extensive safe application of liquid hydrogen propellant. However, the understanding of solid air characteristics still needs to be deepened. Therefore, numerical simulation and low-temperature visual experiments are used to investigate solid air's oxygen and nitrogen distribution and growth characteristics. The results indicate that the phase field model can accurately simulate solid air growth and secondary branching under pure diffusion and forced convection conditions. During the competitive growth of polycrystalline nuclei, the solid air can fuse to form polycrystalline symbiont, and the secondary dendrites can increase the number of fusion sites. The forced convection can increase the risk of solid air in liquid hydrogen, with the highest oxygen content reaching 53.3%. The low-temperature visual experiment device can effectively observe the full-cycle growth process of solid air in liquid hydrogen. When the oxygen concentration in the simulated gas is 15%, the relative oxygen concentration of solid air can reach 33.8%, proving the oxygen enrichment characteristics of solid air. This research can support constructing a safe use system for liquid hydrogen.

引言
1 理论模型
2 实验装置
3 结果与讨论
4 结论

图1 数值计算流程图<br/>Fig.1 Flow chart of numerical calculation

图1 数值计算流程图
Fig.1 Flow chart of numerical calculation

图2 可视化实验装置示意图<br/>Fig.2 Schematic diagram of the visual experiment device

图2 可视化实验装置示意图
Fig.2 Schematic diagram of the visual experiment device

图3 可视化实验装置实物图<br/>Fig.3 Photograph of the visual experiment device

图3 可视化实验装置实物图
Fig.3 Photograph of the visual experiment device

图4 各向异性强度系数对固空相场的影响<br/>Fig.4 Effect of anisotropic strength coefficient on the phase field of solid air

图4 各向异性强度系数对固空相场的影响
Fig.4 Effect of anisotropic strength coefficient on the phase field of solid air

图5 各向异性强度系数对固空温度场的影响<br/>Fig.5 Effect of anisotropic strength coefficient on the temperature field of solid air

图5 各向异性强度系数对固空温度场的影响
Fig.5 Effect of anisotropic strength coefficient on the temperature field of solid air

图6 各向异性强度系数对固空浓度场的影响<br/>Fig.6 Effect of anisotropic strength coefficient on the concentration field of solid air

图6 各向异性强度系数对固空浓度场的影响
Fig.6 Effect of anisotropic strength coefficient on the concentration field of solid air

图7 强制对流下固空生长多物理演化过程<br/>Fig.7 Multi-physical evolution of solid air growth under forced convection

图7 强制对流下固空生长多物理演化过程
Fig.7 Multi-physical evolution of solid air growth under forced convection

图8 强制对流下过冷度对固空生长的影响<br/>Fig.8 Effect of supercooling degree on solid air growth under forced convection

图8 强制对流下过冷度对固空生长的影响
Fig.8 Effect of supercooling degree on solid air growth under forced convection

图9 纯扩散下多晶核固空浓度场演化过程<br/>Fig.9 Evolution process of concentration field of solid air with polycrystalline nuclei under pure diffusion

图9 纯扩散下多晶核固空浓度场演化过程
Fig.9 Evolution process of concentration field of solid air with polycrystalline nuclei under pure diffusion

图10 强制对流下多晶核固空浓度场演化过程<br/>Fig.10 Evolution process of concentration field of solid air with polycrystalline nuclei under forced convection

图10 强制对流下多晶核固空浓度场演化过程
Fig.10 Evolution process of concentration field of solid air with polycrystalline nuclei under forced convection

图11 不同阶段下的液氢固空生长可视化照片<br/>Fig.11 Visualization photos of solid air growth in liquid hydrogen at different stages

图11 不同阶段下的液氢固空生长可视化照片
Fig.11 Visualization photos of solid air growth in liquid hydrogen at different stages

图12 不同取样阶段的固空氧相对浓度值<br/>Fig.12 Relative oxygen concentration values of solid air at different sampling stages

图12 不同取样阶段的固空氧相对浓度值
Fig.12 Relative oxygen concentration values of solid air at different sampling stages

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备注

引言

1 理论模型

2 实验装置

3 结果与讨论

4 结论

期刊信息