Development characteristics of underwater detonation gas jets in confined spaces
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摘要: 为探索脉冲爆轰水冲压发动机水下工作时导水器内燃气射流发展特性, 利用可燃气体的爆轰在水下受限空间内产生脉动气泡, 对爆轰管在圆筒形受限空间内的水下爆轰燃气射流进行了数值仿真与实验验证。基于雷诺时均基本方程组与k-epsilon两方程模型耦合VOF气液界面追踪方法的相输运方程建立受限空间中水下单次燃气射流流场流动模型, 使用OpenFOAM中的CompressibleInterFoam求解器对受限空间中脉冲爆轰燃气射流进行数值求解。结果表明: 受限空间对水下爆轰的前导激波的影响较小, 前导激波幅值与自由空间相比变化不大, 由爆轰燃气射流所引起的压力扰动大幅升高且持续时间明显增加, 受限空间中各处压力显著高于受限空间之外; 受限空间中燃气泡的脉动周期延长至60 ms左右, 然而受限空间径向尺寸对燃气泡的脉动周期影响较小。可见, 受限空间可提高水下爆轰管出口近场压力并延长燃气射流作用时间, 研究结果对脉冲爆轰水冲压发动机推力性能提升方法研究具有重要指导作用。
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关键词:
- 脉冲爆轰水冲压发动机 /
- 水下燃气射流 /
- 受限空间 /
- 气泡脉动
Abstract: To explore the development characteristics of gas jets generated by pulsed detonation hydroramjet working underwater in open-ended water guides, numerical simulations and experimental validations were conducted on underwater detonation gas jets within a cylindrical confined space by utilizing the detonation of combustible gases to generate pulsating bubbles. A flow model of a single gas jet in a confined space was established based on the Reynolds-averaged Navier-Stokes equations, the K-epsilon two-equation model, and the Volume of Fluid (VOF) interface tracking method coupled with the advection equation. The CompressibleInterFoam solver in OpenFOAM was employed for numerical simulations of pulsed detonation gas jets in confined spaces. The results showed that the amplitude of the leading shock wave in the confined space changed insignificantly compared to free underwater space. However, the pressure disturbance caused by the gas jet significantly increased, and its duration prolonged. Additionally, it led to a noticeable increase in pressure within the confined space compared to outside the confined space. The pulsation period of gas bubbles in the confined space extended to approximately 60 ms, and the radial dimension of the confined space had little effect on the fluctuation period of the gas bubbles. It can be seen that confined space can increase the near field pressure at the outlet of the underwater detonation tube and extend the action time of the gas jet. The research results have important guiding significance for the study of thrust performance improvement methods for pulse detonation hydroramjet. -
表 1 数值仿真计算结果与理论值的对比
Table 1. Comparison of numerical simulation results with theoretical values
爆轰参数 C-J理论值 数值计算结果 相对
误差爆轰压力/MPa 3.364 3.658 8.71% 爆轰速度/(m/s) 2 372.900 2 182.000 8.01% 表 2 不同网格尺寸下管内反射激波与前导激波压力值
Table 2. Pressure values of reflected shock wave and leading shock wave in tube with different mesh sizes.
网格尺寸/mm 管内反射激波
压力峰值/MPa前导激波
压力峰值/MPa0.5 3.88 0.96 1.0 3.92 1.17 2.0 4.05 0.84 4.0 4.08 0.70 表 3 不同工况参数
Table 3. Parameters under different working conditions
工况序号 爆轰管填充压力/kPa 无量纲
受限空间直径1 1.0 2 2 3 3 4 4 无壁面 5 1.5 2 6 3 7 4 8 无壁面 9 2.0 2 10 3 11 4 12 无壁面 表 4 燃气泡脉动周期数值计算与实验结果对比
Table 4. Comparison of Numerical Calculation and Experimental Results of Gas Bubble Pulsation Period
受限空间
直径/mm数值计算
结果/ms实验结果
/ms相对
误差/%120 55.0 57.2 3.8 90 60.5 57.6 4.7 60 60.5 58.0 4.3 无壁面 19.0 20.0 5.0 -
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