瓦斯浓度对爆炸传播及瓦斯爆炸诱导煤尘爆炸的影响研究

发布时间：2018-05-21 03:25

本文选题：瓦斯浓度 + 爆炸传播　；参考：《东北大学》2013年博士论文

【摘要】：运用理论分析、实验研究和数值仿真的方法对在不同浓度条件下的瓦斯爆炸压力、火焰传播规律以及瓦斯爆炸诱导沉积煤尘爆炸规律进行了系统深入的研究。在对瓦斯煤尘爆炸的传播过程进行理论分析的基础上,运用中煤科工集团重庆研究院直径700mm的实验管道及断面7.2m2的大型实验巷道分别实验研究了不同浓度条件瓦斯爆炸传播规律的变化及瓦斯爆炸诱导沉积煤尘参与爆炸的过程,在此基础上借助流体模拟软件对其进行了模拟验证分析。通过瓦斯爆炸传播过程的研究得出,瓦斯爆炸过程中点火处的最大压力值并不是整个爆炸过程的最大值,冲击波最大压力在点火处附近先降低,然后上升到某一峰值后再逐步衰减。瓦斯浓度的改变对爆炸过程中压力和火焰的传播规律有明显影响,当测定点距离一定时,压力峰值与浓度呈现二次函数关系,火焰传播速度的倒数与浓度呈现二次函数关系；点火附近火焰传播速度较小,上升到某一峰值后又衰减。通过研究认为,激波及波后气体的湍流效应是引起沉积煤尘扬起的主要因素。煤尘颗粒的表面剪切力在其上扬过程中维持在某一阈值,所以沉积的煤尘颗粒可以维持在一定的速度范围内向上扬起。通过对煤尘颗粒速度场数值模拟的分析,发现沉积煤尘的扬起过程主要由启动、加速和减速三个阶段组成。有煤尘参与的混合爆炸相对于单纯瓦斯爆炸,其爆炸产生的冲击波及火焰锋面不易衰减,传播速度更快,持续时间更长,压力峰值更高,波及范围更广；在瓦斯爆炸诱导沉积煤尘爆炸的起始阶段,爆炸产生的正压区持续时间更长,并且爆炸压力在较长时间内产生持续的回升现象,破坏性更大；最大爆炸压力的出现时间并非沿着管道传播距离的加长而依次后延,也并非随最大爆炸压力的大小依次出现。瓦斯爆炸游到沉积煤尘爆炸的过程分为单纯瓦斯起爆阶段、沉积煤尘卷扬参与爆炸阶段(即瓦斯爆炸产生的冲击波与沉积煤尘作用、沉积煤尘卷扬起并被与瓦斯爆炸的火焰波引爆阶段)、瓦斯煤尘混合爆炸传播阶段和爆炸衰减等四个阶段。根据研究得出,在起爆阶段压力峰值出现时间最早,煤尘卷扬参与爆炸阶段压力峰值出现时间远远晚于瓦斯煤尘混合爆炸传播阶段,这是由于沉积煤尘卷扬参与爆炸的特点决定的,瓦斯煤尘爆炸传播衰减阶段压力值的出现的时间最晚。研究得到的这些结论,对有效防治煤矿爆炸灾害防治、降低爆炸灾害所造成的损失以及煤矿瓦斯煤尘爆炸事故的分析调查具有重要意义。
[Abstract]:By means of theoretical analysis, experimental study and numerical simulation, the pressure of gas explosion, the law of flame propagation and the law of depositional coal dust explosion induced by gas explosion are studied systematically and deeply. Based on the theoretical analysis of the propagation process of gas and coal dust explosion, Using the experimental pipe of diameter 700mm of Chongqing Research Institute of China Coal Science and Technology Group and the large-scale experimental roadway of cross section 7.2m2, the variation of the propagation law of gas explosion and the process of taking part in the explosion of deposited coal dust induced by gas explosion were studied respectively. On this basis, the fluid simulation software is used to verify and analyze it. Through the study of the gas explosion propagation process, it is concluded that the maximum pressure of the ignition fire is not the maximum value of the whole explosion process, and the maximum pressure of the shock wave decreases first near the igniting fire. Then rise to a certain peak and then gradually attenuate. The change of gas concentration has obvious influence on the pressure and flame propagation law in the process of explosion. When the measuring point distance is fixed, the relationship between the pressure peak value and the concentration is quadratic, and the reciprocal of flame propagation velocity is quadratic function relationship with the flame concentration. The flame propagates slowly near the ignition, and then attenuates after rising to a certain peak. It is considered that the turbulent effect of the gas behind the shock wave is the main factor to cause the rising of sedimentary coal dust. The surface shear force of coal dust particles is maintained at a certain threshold value during the rising process, so the deposited coal dust particles can be raised upward in a certain velocity range. Through the numerical simulation of velocity field of coal dust particles, it is found that the raising process of deposited coal dust consists of three stages: starting, accelerating and decelerating. Compared with the pure gas explosion, the mixed explosion with coal dust is not easy to attenuate, propagate faster, last longer, the pressure peak value is higher, and the range is wider. In the initial stage of coal dust explosion induced by gas explosion, the barotropic zone produced by the explosion lasts longer, and the explosion pressure produces a sustained recovery phenomenon in a longer period of time, which is more destructive. The occurrence time of the maximum explosion pressure is not followed by the increase of the propagation distance of the pipeline, nor is it followed by the magnitude of the maximum explosion pressure. The process from gas explosion to sedimentary coal dust explosion can be divided into simple gas initiation stage, and sedimentary coal dust hoisting takes part in the explosion stage (that is, the shock wave produced by gas explosion and the effect of deposited coal dust). The depositional coal dust is hoisted and is detonated by the flame wave with the gas explosion, the gas coal dust mixed explosion propagation stage and the explosion attenuation stage. According to the study, the peak pressure appeared the earliest time in the initiation stage, and the coal dust hoisting involved in the explosion phase, the time of the peak pressure appeared much later than the gas coal dust mixed explosion stage. It is decided by the characteristics that the deposited coal dust is involved in the explosion, and the pressure value of the gas coal dust explosion propagation attenuation stage is the latest. These conclusions are of great significance to the prevention and control of coal mine explosion disaster, the reduction of the loss caused by explosion disaster and the analysis and investigation of coal mine gas and coal dust explosion accident.
【学位授予单位】：东北大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TD712.7

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