褐煤爆炸冲击气流传播特性与CO生成特性数值模拟

刘天奇

doi:10.11883/bzycj-2018-0297

褐煤爆炸冲击气流传播特性与CO生成特性数值模拟

doi: 10.11883/bzycj-2018-0297

刘天奇

沈阳航空航天大学安全工程学院，辽宁沈阳 110136

基金项目: 国家自然科学基金（51774168）；博士科研启动基金（18YB37）

详细信息

作者简介:
刘天奇（1990－　），男，博士，讲师，ltq613@163.com

中图分类号: O389; X936
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出版历程
- 收稿日期: 2018-08-13
- 修回日期: 2018-11-02
- 刊出日期: 2019-10-01

Numerical simulation on characteristics of impinging air flow propagationand CO formation in lignite explosion

LIU Tianqi

College of Safety Engineering, Shenyang Aerospace University, Shenyang 110136, Liaoning, China

摘要

摘要: 为研究褐煤爆炸过程中冲击气流传播特性及CO毒气生成特性，以水平管道煤尘爆炸实验装置为依托，按1∶1比例建立水平管道几何模型，在构建煤尘爆炸动力传播特性数学模型的基础上，展开冲击气流传播特性与CO生成特性模拟分析。结果表明：通过对比不同时刻褐煤爆炸火焰传播距离模拟值与实测值，验证了模拟方法的可靠性。以冲击气流传播速度模拟值划分空间区域，得到：z=0～0.1 m为初始扬尘区，z=0.1～0.42 m为冲击气流速度跃升区，z=0.42～0.98 m为冲击气流高速传播区，z=0.98～1.4 m为冲击气流缓冲区。z=0.2 m与z=0.4 m截面上距圆心越远，冲击气流传播速度越大，这是由流体流动的“壁面效应”导致的，壁面附近空隙率大于流体内部，流动时所受阻力比较小，因此出现冲击气流在近壁处流速较大的分布特征。模拟CO毒气产物生成特性发现，管内z=0.3～0.6 m为CO质量分数相对最高的空间范围，局部最高达到0.024%～0.026%。在z＞0.7 m时，由于颗粒受重力作用，同时爆炸产生的高温气体受浮力作用，导致CO气体产物出现下沉的趋势。
- 煤尘爆炸 /
- 冲击气流 /
- CO毒气产物 /
- 褐煤
Abstract: In this paper we established a horizontal pipeline geometric model based on the horizontal pipeline coal dust explosion experimental device to study the characteristics of impinging airflow and CO gas generation during lignite explosion, and constructed the mathematical model of the coal-dust explosion dynamic propagation according to the 1∶1 ratio, with the characteristics of the airflow propagation and CO generation simulated. The results verified the reliability of the simulation by comparing the simulated and measured values of the lignite explosion flame propagation distance at different times. The spatial region is divided by the simulated velocity of the impinging airflow: z=0−0.10 m is the initial dusting zone, z=0.10−0.42 m is the impact airflow velocity jump zone, and z=0.42−0.98 m is the high velocity propagation zone of the impinging airflow. z=0.98−1.40 m is the impinging airflow buffer. The farther away from the centers of the z=0.20 m and z=0.40 m cross-sections, the greater the velocity of the impinging airflow, resulting from the " wall effect” of the fluid flow. The void ratio near the wall is larger than that in the inside of the fluid, and the resistance is weak when flowing. Therefore, the impinging airflow exhibits a relatively greater flow velocity near the wall. The simulation of the formation of CO gas products shows that z=0.30−0.60 m in the tube is the spatial range with the highest CO mass fraction, and the local maximum is 0.024%−0.026%. At z＞0.70 m, the particles were subjected to the gravity, and the high-temperature gas generated by the explosion was subjected to the buoyancy, resulting in a tendency of the CO gas product to sink.
- explosion of coal dust /
- impinging airflow /
- CO toxic gas product /
- lignite

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图 1 水平管道煤尘爆炸装置结构

Figure 1. Coal dust explosion device of horizontal tube

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图 2 划分网格的几何模型

Figure 2. Geometry model of the mesh

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图 3 初始高温点火区（点火温度1 373 K）

Figure 3. Initial high-temperature ignition zone (ignition temperature=1 373 K)

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图 4 不同时刻y=0截面火焰温度云图

Figure 4. Flame temperature’s nephogram of y=0 cross section at different time

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图 5 y=0截面冲击气流传播速度云图

Figure 5. Impinging airflow propagation velocity’s nephogram of y=0 cross section

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图 6 y=0截面冲击气流传播速度等值线图

Figure 6. Impinging airflow propagation velocity’s contour of y=0 cross section

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图 7 沿z方向不同距离管道截面冲击气流传播速度云图

Figure 7. Impinging airflow propagation velocity’s nephogram at different positions along z direction

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图 8 y=0截面CO质量分数云图

Figure 8. Mass fraction’s nephogram of CO in y=0 cross section

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图 9 沿z方向不同距离管道截面CO质量分数云图

Figure 9. Mass fraction’s nephogram of CO at different positions along z direction

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表 1 不同时刻爆炸火焰传播距离

Table 1. Flame propagation distance of explosion at different time

时间 t/ms	火焰传播距离 l/cm	时间 t/ms	火焰传播距离 l/cm
0	0	625	60
125	47	750	41
250	60	875	15
375	65	1 000	0
500	74

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表 2 人体在CO气体环境下的反应

Table 2. Human reactions under condition of CO

CO体积分数/%	CO质量分数/%	人体反应	CO体积分数/%	CO质量分数/%	人体反应
0.02	0.019	2～3 h：轻微头痛	0.16	0.155	1 h：四肢无力
0.04	0.039	1～2 h：眩晕	0.32	0.309	20 s：丧失知觉
0.08	0.077	45 s：耳鸣头痛	1.32	1.276	1～3 s：死亡

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