﻿ 障碍物排列方式对非均匀氢-空气混合物爆炸特性的影响
 舰船科学技术  2024, Vol. 46 Issue (11): 17-22    DOI: 10.3404/j.issn.1672-7649.2024.11.004 PDF

Effect of obstacle arrangement on explosion characteristics of inhomogeneous hydrogen-air mixture
QI Baiyi, YANG Guogang, LI Shian, SHEN Qiuwan, SHENG Zhonghua, SUN Han, AN Zuxu, JIA Huidong
College of Marine Engineering, Dalian Maritime University, Dalian 116026, China
Abstract: The effect of different obstacle arrangements on the explosion flame dynamics of inhomogeneous hydrogen-air mixture is investigated by numerical simulation, and the explosion characteristic parameters predicted by the simulation are all in good agreement with the experimental results. The simulation results show that the premixed flame undergoes four stages of evolution in the tube: spherical flame, finger flame, conical flame, and flocculent flame. When the flame passes through the obstacle, the flow field is seriously unstable, resulting in serious distortion of the flame. When the obstacle is arranged on both sides, the flame reaches the pipe outlet first, and the pressure reaches the peak the fastest. The obstacle at the tube top can significantly increase the explosion pressure, and compared with the bottom arrangement, the explosion peak overpressure increases by 23% and 74% when the obstacle is arranged on both sides and at the top of the tube, respectively. This study can provide theoretical guidance for hydrogen safety planning and explosion protection.
Key words: obstacle arrangement     numerical simulation     inhomogeneous mixture     hydrogen explosion     flame structure
0 引　言

1 数值方法 1.1 数学模型 1.1.1 控制方程

 $\frac{{\partial \rho }}{{\partial t}} + \frac{\partial }{{\partial {x_i}}}\left( {\rho {u_i}} \right) = 0，$ (1)
 $\frac{\partial }{{\partial t}}\left( {\rho {u_i}} \right) + \frac{\partial }{{\partial {x_j}}}\left( {\rho {u_j}{u_i}} \right) = - \frac{{\partial p}}{{\partial {x_j}}} + \frac{{\partial {\tau _{ij}}}}{{\partial {x_j}}} + \rho {g_i}，$ (2)
 $\frac{\partial }{{\partial t}}\left( {\rho E} \right) + \frac{\partial }{{\partial {x_j}}}\left( {\rho {u_j}{c_p}T + p} \right) = {\mu _i}\left( {\frac{{\partial p}}{{\partial {x_i}}}} \right) + \frac{{\partial {u_i}}}{{\partial {x_i}}}{\left( {{\tau _{ij}}} \right)_{e f f}} - \frac{{\partial {q_i}}}{{\partial {x_i}}} ，$ (3)
 $pM = \rho RT 。$ (4)

1.1.2 湍流模型

 $\frac{\partial }{{\partial t}}\left( {\rho k} \right) + \frac{\partial }{{\partial {x_i}}}\left( {\rho k{u_i}} \right) = \frac{\partial }{{\partial {x_j}}}\left( {{\Gamma _k}\frac{{\partial k}}{{\partial {x_j}}}} \right) + {G_k} - {Y_k} + {S_k} + {G_b}，$ (5)
 $\frac{\partial }{{\partial t}} \left( {\rho \omega } \right) + \frac{\partial }{{\partial {x_i}}} \left( {\rho \omega {u_i}} \right) = \frac{\partial }{{\partial {x_j}}} \left( {{\Gamma _\omega } \frac{{{\partial _\omega }}}{{\partial {x _j}}}} \right) + {G_\omega } - {Y_\omega } + {D_\omega } + {S_\omega } + {G_{\omega b}} ，$ (6)

 ${D_\omega } = 2\left( {1 - {F_1}} \right)\rho \frac{1}{{\omega {\sigma _{\omega ,2}}}}\frac{{\partial k}}{{\partial {x_j}}}\frac{{\partial \omega }}{{\partial {x_j}}}，$ (7)
 ${F_1} = \tan {\text h} \left( {\varPhi _1^4} \right) ，$ (8)
 ${\Phi _1} = \min \left[ {\max \left( {\frac{{\sqrt k }}{{0.09\omega y}},\frac{{500\mu }}{{\rho {y^2}\omega }}} \right),\frac{{4\rho k}}{{{\sigma _{\omega ,2}}D_\omega ^ + {y^2}}}} \right] ，$ (9)
 $D_\omega ^ + = \max \left[ {2\rho \frac{1}{{{\sigma _{\omega ,2}}}}\frac{1}{\omega }\frac{{\partial k}}{{\partial {x_j}}}\frac{{\partial \omega }}{{\partial {x_j}}},{{10}^{ - 10}}} \right] 。$ (10)

 ${\mu _t} = \frac{{\rho k}}{\omega }\frac{1}{{\max \displaystyle \left[ {\frac{1}{{{\alpha ^*}}},\frac{{S{F_2}}}{{{a_1}\omega }}} \right]}} ，$ (11)
 ${F_2} = \tan {\text h} \left( {\varPhi _2^2} \right)，$ (12)
 ${\varPhi _2} = \max \left[ {2\frac{{\sqrt k }}{{0.09\omega y}},\frac{{500\mu }}{{\rho {y^2}\omega }}} \right] 。$ (13)

1.1.3 燃烧模型

 $\frac{\partial }{{\partial t}}\left( {\rho c} \right) + \nabla \cdot \left( {\rho {u_j}c} \right) = \nabla \cdot \left( {\left( {\frac{k}{{{C_p}}} + \frac{{{\mu _t}}}{{S{c_t}}}} \right)\nabla c} \right) + {\rho _u}{U_t}\left| {\nabla c} \right|。$ (14)

 ${U_t} = A{\left( {{u^{'}}} \right)^{3/4}}U_l^{1/2}{\alpha ^{ - 1/4}}\ell _t^{1/4}。$ (15)

1.2 物理模型

 图 1 不同障碍物排列方式管道几何模型图 Fig. 1 Geometric model diagram of ducts with different obstacle arrangements

 图 2 氢气浓度梯度分布 Fig. 2 Hydrogen concentration gradient distribution
1.3 求解器设置

1.4 网格划分

 图 3 网格独立性验证 Fig. 3 Grid independence verification
2 结果与分析 2.1 模型验证

 图 4 数值模拟与实验结果的比较 Fig. 4 Comparison of numerical simulation and experimental results
2.2 障碍物排列方式对火焰结构的影响

 图 5 不同障碍物排列方式管道内火焰结构和流场变化 Fig. 5 Variations of flame structure and flow field in ducts with different obstacle arrangements
2.3 障碍物排列方式对火焰传播速度的影响

 图 6 不同障碍物排列方式管道内火焰锋面位置和火焰传播速度随时间的变化 Fig. 6 Variations of flame front position and flame propagation velocity with time in ducts with different obstacle arrangements
2.4 障碍物排列方式对爆炸超压的影响

 图 7 不同障碍物排列方式管道内爆炸超压和超压增长率随时间的变化 Fig. 7 Variations of explosion overpressure and growth rate of overpressure with time in ducts with different obstacle arrangements
3 结　语

1）在不同障碍物排列方式情况下，火焰传播过程中经历了球形火焰、指形火焰、锥形火焰和絮状火焰4个阶段。当火焰穿过障碍物时，涡流的扰动作用是火焰形态变化的主要原因。

2）障碍物对早期火焰传播的影响不大。障碍物布置在管道顶部时，火焰锋面靠近障碍物时受到的抑制作用更强，穿过障碍物后的火焰传播速度更快。

3）随着顶部障碍物高度的增加，混合物爆炸峰值压力显著提高。障碍物布置在管道两侧和顶部时的峰值压力分别比底部布置时高23%和74%。

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