﻿ 基于CFD的燃烧轻气炮发射过程仿真
 舰船科学技术  2022, Vol. 44 Issue (10): 180-184    DOI: 10.3404/j.issn.1672-7649.2022.10.039 PDF

Simulation for launch process of combustion light gas gun based on CFD
HU Bin, WANG Zhen, HE Hang, PENG Song-jiang
The 713 Research Institute of CSSC, Zhengzhou 450015, China
Abstract: Aiming at the internal ballistic control problem in the firing process of combustion light gas gun, the 19-step detailed chemical reaction mechanisms of burning hydrogen-oxygen were combined with the basic model of turbulent flow, considering the influence of both chemical kinetics and turbulence effect. Then numerical simulation calculations were carried out to analyze the influence of different initial conditions on the interior ballistic characteristics of the combustion light gas gun. The results show that the hydrogen-oxygen combustion in the chamber was in the form of turbulent flame combustion, the initial temperature and pressure can significantly affect the hydrogen-oxygen combustion process and change the interior ballistic performance. The volume of combustion chamber has great influence on energy utilization when the gas filling density in chamber remains unchanged. These simulation results provide a theoretical basis for further research of the combustion light gas gun.
Key words: turbulent combustion     CFD     interior ballistics     combustion light gas gun
0 引　言

1 模型描述 1.1 计算模型与网格设置

 图 1 燃烧轻气炮基本结构简化模型 Fig. 1 The simplified structure model of combustion light gas gun
1.2 流动控制方程

 $\frac{{\partial \rho }}{{\partial t}} + \frac{\partial }{{\partial \mathop \chi \nolimits_j }}\left( {\mathop {\rho \upsilon }\nolimits_j } \right) = 0,$ (1)
 $\frac{\partial }{{\partial t}}\left( {\rho \mathop \upsilon \nolimits_i } \right) + \frac{\partial }{{\partial \mathop \chi \nolimits_j }}\left( {\rho \mathop \upsilon \nolimits_i \mathop \upsilon \nolimits_j + \frac{2}{3}\mathop \delta \nolimits_{ij} \rho k} \right) = - \frac{{\partial p}}{{\partial \mathop \chi \nolimits_i }} + \frac{{\partial \mathop \tau \nolimits_{ij} }}{{\partial \mathop \chi \nolimits_j }},$ (2)
 $\frac{\partial }{{\partial t}}\left( {\rho E} \right) + \frac{\partial }{{\partial \mathop \chi \nolimits_j }}\left( {\rho \mathop \upsilon \nolimits_j H} \right) = \frac{\partial }{{\partial \mathop \chi \nolimits_j }}\left( {\rho \mathop a\nolimits_{eff} \frac{{\partial H}}{{\partial \mathop \chi \nolimits_j }} + \mathop \tau \nolimits_{ij} \mathop \upsilon \nolimits_i } \right) ,$ (3)
 $\frac{\partial }{{\partial t}}\left( {\rho \mathop Y\nolimits_k } \right) + \frac{\partial }{{\partial \mathop \chi \nolimits_j }}\left( {\rho \mathop Y\nolimits_k \mathop u\nolimits_j } \right) = \frac{\partial }{{\partial \mathop x\nolimits_j }}\left( {\rho \mathop D\nolimits_{eff} \frac{{\partial \mathop Y\nolimits_k }}{{\partial \mathop \chi \nolimits_j }}} \right) + \mathop {\dot \omega }\nolimits_{_k}。$ (4)

1.3 湍流模型

 $\begin{split} \frac{{\partial \left( {\rho k} \right)}}{{\partial t}} + \frac{{\partial \left( {\rho k\mathop u\nolimits_i } \right)}}{{\partial \mathop \chi \nolimits_i }} = &\frac{\partial }{{\partial \mathop \chi \nolimits_j }}\left[ {\left( {\mu + \frac{{\mathop \mu \nolimits_t }}{{\mathop \sigma \nolimits_k }}} \right)\frac{{\partial k}}{{\partial \mathop \chi \nolimits_j }}} \right] +\\ & \mathop G\nolimits_k + \mathop G\nolimits_b - \rho \varepsilon - \mathop Y\nolimits_M + \mathop S\nolimits_k , \end{split}$ (5)
 $\begin{split} \frac{{\partial \left( {\rho \varepsilon } \right)}}{{\partial t}} +& \frac{{\partial \left( {\rho \varepsilon \mathop u\nolimits_i } \right)}}{{\partial \mathop \chi \nolimits_i }} = \frac{\partial }{{\mathop {\partial \chi }\nolimits_j }}\left[ {\left( {\mu + \frac{{\mathop \mu \nolimits_t }}{{\mathop \sigma \nolimits_\varepsilon }}} \right)\frac{{\partial \varepsilon }}{{\partial \mathop \chi \nolimits_j }}} \right] + \\ & \mathop C\nolimits_{1\varepsilon } \frac{\varepsilon }{k}\left( {\mathop G\nolimits_k +\mathop C\nolimits_{3\varepsilon } \mathop G\nolimits_b } \right) - \mathop C\nolimits_{2\varepsilon } \rho \frac{{\mathop \varepsilon \nolimits^2 }}{k} + \mathop S\nolimits_\varepsilon。\end{split}$ (6)

1.4 燃烧模型

 $w = \mathop k\nolimits_0 \mathop T\nolimits^b \mathop e\nolimits^{ - E/RT} \left[ A \right]\left[ B \right]。$ (7)

2 计算结果与分析 2.1 模型验证

2.2 氢氧燃烧过程

 图 2 初始阶段温度变化云图 Fig. 2 The cloud image of temperature in initial stage
2.3 初始温度对内弹道性能的影响

 图 3 不同初始温度对膛压和弹丸速度的影响 Fig. 3 The influence of different initial temperatures on chamber pressure and muzzle velocity
2.4 初始压力对内弹道性能的影响

 图 4 不同初始压力对膛压和弹丸速度的影响 Fig. 4 The influence of different initial pressures on chamber pressure and muzzle velocity
2.5 燃烧室容积对内弹道性能的影响

 图 5 不同燃烧室容积对膛压和弹丸速度的影响 Fig. 5 The influence of different chamber volumes on chamber pressure and muzzle velocity
3 结　语

1）膛内氢氧燃烧呈现出湍流火焰特征，随着燃烧火焰的增大，湍流作用加剧，火焰传播速度加快；

2）初始温度对氢氧燃烧过程影响较大，初始温度降低，氢氧发射药总能量增大，膛压增大，压力波动减小，弹丸初速增加；

3）初始压力增大时，发射药总能量增加，膛压增大，弹丸初速增大，实际应用中应该合理地选择发射药气体的初始装填压力，避免膛压过高；

4）保持装填气体密度不变，扩展燃烧室容积可以在一定程度上提高弹丸初速，但是能量利用率降低，做功能力下降。

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