Simulation analysis on structure safety of coal mine mobile refuge chamber under explosion load

In order to check structural strength of coal mine mobiles refuge chamber, and do security evaluation of the mobile refuge chamber, a refuge chamber model was established, then a finite element method was instituted for it to ensure the refuge chamber would not be severely damaged when gas or coal dust explosion suddenly happened. A triangle shock wave with 1.2 MPa over-pressure, 300 ms lasting time was settled. Explicit nonlinear dynamic analysis program was used to simulate response of the refuge chamber. The maximum stress was 244 MPa, located in central part of sides and tail end of the last capsule. The maximum displacement was 29.32 mm, located in central part of sides and tail end of the last capsule. The calculation indicated that the refuge chamber was not obviously damaged. It could reliable work to meet safety requirements. Compared with the reported experimental results, the simulation method was verified. Based on analysis, suggestions were put forward for further improving.     

Dynamic response characteristics and structural optimization of isolation seal under the impact of gas explosion

Either in the chemical process plants or in the underground infrastructures, the isolation seal is regularly used to separate the working sections and inactive sections, or to isolate the possible explosion sites in order to avoid any domino effects. Due to differences in accumulation space or ignition point locations, pressure on the seal can vary when an explosion occurs. Thus, the safety and reliability of seals are crucial to maintaining safety in process industry. This paper focuses on seals constructed with concrete and loess materials, and examines the dynamic response characteristics of the gas explosion wave on the seal through sample experiments and numerical simulation metods. The study proposes an optimized design for the explosion-proof structure of the wedge-shaped and spherical seal, which can provide a technical basis for the explosion-proof and anti-explosion measures of various sealed walls. These research findings can also serve as a basis for improving the construction quality of seals.     

煤矿井下移动救生舱的设计思路

矿用移动救生舱将成为我国煤矿井下矿工的一种重要逃生装备。本文简述了矿用救生舱在国内外的研究与应用现状,分析了在现阶段,我国有关企业单位研制煤矿井下移动救生舱时,在功能定位、舱内设施、检测检验、使用与维护等方面必须注意的几个问题。     

旬东煤矿井下永久避难硐室构建研究

避难硐室的构建研究对硐室安全避险功能的实现具有重要意义。根据旬东井下人员分布及巷道布置情况,确定利用4-2采煤区现有巷道构建100人规模永久避难硐室;根据巷道尺寸、人均面积及设备体积等,计算得硐室有效宽度为4.6m,高度为3.5m,总长度为63.4m,人均面积为1.2m2;通过气密试验,测定0.135MPa避险区内外压差可达1980Pa;通过分析人员避险需求,确定旬东永久避难硐室生命保障系统由防火防爆系统、密闭缓冲系统、气幕隔绝系统、供氧系统、制冷除湿系统及附属系统组成。     

Influence of sewage culvert cover plate thickness on dynamic response and damage of the cover plate under gas explosion

In order to address the risk of combustible gas explosions in sewage culverts, a numerical model was established using ANSYS/LS-DYNA software. The model consisted of a culvert and a cover plate, and was used to study the effect of cover plate thickness (ranging from 0.08 m to 0.12 m) on the dynamic response and damage of the structure under explosive loads. The results indicated that, during the loading negative pressure stage, the equivalent stress peak value of the central monitoring unit of the cover plate first increased and then decreased with increasing cover plate thickness. Additionally, the maximum principal stress peak value first decreased and then increased, while the maximum shear stress peak value first increased and then decreased. During the loading positive pressure stage, the maximum principal strain peak value of the monitoring unit decreased overall with increasing cover plate thickness. However, the equivalent plastic strain peak value initially increased and then decreased gradually. The equivalent strain indicated that plastic damage occurred in the cover plate. Beyond a thickness of 0.11 m, increasing the cover thickness did not appear to enhance its resistance to plastic damage. The damage analysis revealed that as cover plate thickness increased, the peak displacement and velocity of the monitoring unit continued to decrease, while the overall stability and explosive resistance of the cover plate increased. Additionally, the number of damaged fragments decreased. However, once the cover plate thickness reached 0.11 m, the bonding performance of the reinforced concrete structure had been fully developed, increasing the thickness of the cover plate no longer had a significant impact on the explosive resistance of the cover plate.     

煤矿瓦斯爆炸发展规律及防治的综述及展望

针对瓦斯爆炸事故在矿井开采中的危害及防治,从爆炸发展规律和爆炸防治两大方面对国内外瓦斯爆炸研究状况进行了综合评述.国内外学者通过理论法、实验法、数值模拟法对瓦斯爆炸进行研究,瓦斯爆炸发展规律方面的研究涉及到瓦斯爆炸的机理、瓦斯组分及浓度对爆炸发展规律的影响、爆炸发生的条件及危害、爆炸过程中的燃烧阶段变化及流体流动状态变...     

Suppression of gas explosion using vacuum chamber at different break-up times of diaphragm

Vacuum chamber is a new method to suppress the gas explosion. The explosion propagation characteristics have been studied in an L-shaped channel (tubes joined a right angle) with a vacuum chamber in the region of joining of the tubes. The vacuum chamber separated from the inner tubular space with the help of a diaphragm pierced by firing pin. The results demonstrate that the effect of explosion suppression of vacuum chamber is related to the break-up time of diaphragm and the position of the explosive flame front. When the diaphragm breaks up, the shorter the distance of flame front propagation is, the closer the flame front gets to the vacuum chamber, and the better effect of explosion suppression is, conversely, the worse the effect of explosion suppression is.     

Coupling effects of foam ceramics on the flame and shock wave of gas explosion

The coupling of gas explosion flame and shock wave is analyzed. In the gas explosion process, shock wave is affected by the flame directly, and shock wave also induces the flame. Inhibiting explosion can be achieved by the interference between the flame and shock wave propagation. If the coupling effects can be damaged, the adverse effects caused by the explosion should be mitigated and controlled. According to the structure characteristics of foam ceramics, the coupling effects mechanism of ceramic foam on gas explosion flame and shock wave is researched. When the explosion goes through the structure of foam ceramics, the flame can be quenched and the shock wave be attenuated. After the flame is quenched, the supply of precursor shock wave energy is cut off. Due to lack of energy supply, the destructive effects of blast wave will be reduced effectively. Coupling effects of the flame and shock wave can be damaged by the special structure of foam ceramics. Studies suggest that a certain function to represent the structure characteristics of foam ceramics must exist. For a certain material of foam ceramics, the sure porosity δ and the pore diameter d also can be get, which is the key to research and develop foam ceramic suppression technology of gas explosion.     

矿井避难硐室研究与设计

基于井下发生瓦斯、煤尘事故时,人员伤亡的75％是由于有害气体中毒而死亡,而井下自救器又无法提供长时间的氧气供应这一事实。本文提出了建立井下避难硐室的基本要求,从通风、供氧、防火、供电等12个方面做出了设计,因此建立井下避难硐室,对于爆炸事故的幸存者来说,就是一个通向求生道路的中转加油站。     

Influence of vacuum degree on the effect of gas explosion suppression by vacuum chamber

In order to study the influence of vacuum degree on gas explosion suppression by vacuum chamber, this study used the 0.2 mm thick polytetrafluoroethylene film as the diaphragm of vacuum chamber to carry out a series of experiments of gas explosion suppression by vacuum chamber with the vacuum degree from −0.01 MPa to −0.08 MPa. The experimental results show that: under the condition of any vacuum degree, vacuum chamber can effectively suppress the explosion flame and overpressure; as vacuum degree changes, the effect of gas explosion suppression using vacuum chamber is slightly different. Vacuum chamber has obvious influence on propagation characteristics of the explosion flame. After explosion flame passes by vacuum chamber, the flame signal weakens, the flame thickness becomes thicker, and the flame speed slows down. With the increase of the vacuum degree of vacuum chamber, the flame speed can be prevented from rising early by vacuum chamber. The higher the vacuum degree is, the more obviously the vacuum chamber attenuates the explosion overpressure, the smaller the average overpressure is, and the better effect of the gas explosion suppression is. Vacuum chamber can effectively weaken the explosion impulse under each vacuum degree. From the beginning of −0.01 MPa, the vacuum chamber can gradually weaken explosion impulse as the vacuum degree increases, and the effect of gas explosion suppression gradually becomes better. When the vacuum degree is greater than −0.04 MPa, the increase of vacuum degree can make the explosion overpressure decrease but have little influence on the explosion impulse. Therefore, the vacuum chamber has the preferable suppression effect with equal to or greater than −0.04 MPa vacuum degree.     

矿用可移动式救生舱隔热性能研究与试验

根据救生舱舱体结构,构建舱体隔热层填充材料隔热性能测定系统;利用该系统,分别测定了硅酸铝针刺毯、复合硅酸盐毡和膨胀蛭石粉自身的隔热性能;结合舱体结构特点,制作救生舱模拟结构层;在钢板内侧粘贴铝箔,构建双层防护隔热结构;测定结果表明复合硅酸盐毡最适合作为救生舱隔热层的填充材料;利用修正函数计算出复合硅酸盐毡的厚度为100mm,对该厚度材料的隔热性能进行测定,试验结果证明其可行。     

Effects of premixed methane concentration on distribution of flame region and hazard effects in a tube and a tunnel gas explosion

Study of flame distribution laws and the hazard effects in a tunnel gas explosion accident is of great importance for safety issue. However, it has not yet been fully explored. The object of present work is mainly to study the effects of premixed gas concentration on the distribution law of the flame region and the hazard effects involving methane-air explosion in a tube and a tunnel based on experimental and numerical results. The experiments were conducted in a tube with one end closed and the other open. The tube was partially filled with premixed methane-air mixture with six different premixed methane concentrations. Major simulation works were performed in a full-scale tunnel with a length of 1000 m. The first 56 m of the tunnel were occupied by methane–air mixture. Results show that the flame region is always longer than the original gas region in any case. Concentration has significant effects on the flame region distribution and the explosion behaviors. In the tube, peak overpressures and maximum rates of overpressure rise (dp/dt)_max for mixtures with lower and higher concentrations are great lower than that for mixtures close to stoichiometric concentration. Due to the gas diffusion effect, not the stoichiometric mixture but the mixture with a slightly higher concentration of 11% gets the highest peak overpressure and the shock wave speed along the tube. In the full-scale tunnel, for fuel lean and stoichiometric mixture, the maximum peak combustion rates is achieved before arriving at the boundary of the original methane accumulation region, while for fuel rich mixture, the maximum value appears beyond the region. It is also found that the flame region for the case of stoichiometric mixture is the shortest as 72 m since the higher explosion intensity shortens the gas diffusion time. The case for concentration of 13% can reach up to a longest value of 128 m for longer diffusion time and the abundant fuel. The “serious injury and death” zone caused by shock wave may reach up to 3–8 times of the length of the original methane occupied region, which is the widest damage region.     

A study on the obstacle-induced variation of the gas explosion characteristics

A study on the variation of the gas explosion characteristics caused by the built-in obstacles was conducted in enclosed/vented gas explosion vessels. It has been well known that the obstacles in pipes and long ducts would accelerate the flame propagation, and cause the transition from deflagration to detonation. In this study, the explosion characteristics and the flame behavior of vented explosions and constant-volume explosions were investigated. Experiments were carried out in a 270-liter and 36-liter hexahedron vessels filled with LPG–air mixture. The explosion characteristics of the gas mixture were determined by using a strain-responding pressure transducer. The flame behavior was recorded by using a high-speed video camera. The shape and the size of the obstacle, and the gas concentration, were adjusted in the experiments.

It can be seen from the experimental results that, instead of being accelerated, the flame propagation inside the explosion vessel is decelerated by the plate obstacles fixed at the bottom of the vessel. Also, the characteristics of the enclosed explosion are not so affected by the built-in obstacles as those of the vented explosion are. It is believed that the eddy-induced turbulence behind the obstacle decelerates the flame propagation.     

煤矿瓦斯爆炸事故的应急救援物资调度模型研究

矿井瓦斯爆炸事故是煤矿安全生产中最严重的事故之一.为确保事故后应急救援的高效开展及减少应急物资调度过程中的经济损失,在以调度时间为第一的前提下,结合煤矿瓦斯爆炸事故实际,引入伤亡性和经济性两个优化目标,构建了一种在多出救点、多物资和多受灾点约束条件下的多目标应急物资调拨模型,并运用加权算法基本思想,确定了决策效用函数,同时结合瓦斯爆炸事故的时间紧迫度,在保证物资连续消耗的条件下,求解最优物资调度方案,并通过实例验证了可行性.     

基于灰色-物元模型的煤矿瓦斯爆炸风险评估

为了明确风险因素间的作用路径并提出科学可行的瓦斯爆炸灾害风险评估方法,首先基于3类危险源理论梳理分析以往典型瓦斯爆炸案例,识别并提取14个影响因素;然后通过集成灰色系统理论和物元可拓模型,构建灰色-物元评估模型;最后以山西省某煤矿的实际调研数据为例,计算各影响因素的权重和关联函数,梳理风险因素致灾的逻辑关系,得出该矿井...     

Study on acceleration and suppression properties of coal gangue with different void fractions on gas explosion propagation

Gas explosion is one of the main disasters in coal mining. Plenty of coal gangue are generally distributed in the disaster areas in gob. Experiments were carried out to explore the propagation law of the gas explosion distributed by coal gangue. The variation characteristics of the overpressure, pressure rise rate, and flame shape with void fractions were analyzed. The results showed that the effect of the coal gangue on the explosion intensity changed from suppression to acceleration with the increase of void fraction, the flame front upstream blockage area changed from laminar state to turbulent divergent state, and a reverse flame was formed. When the void fraction of the coal gangue was 0.50–0.65, the maximum overpressure downstream of the blocked area were positively correlated with the void fraction and the critical suppression range was between 0.50 and 0.55. When the void fraction was lower than 0.50, the flame was quenched in the coal gangue, neither the flame nor the pressure could pass through the blocked area. It is helpful to guide the improvement of coal recovery process to avoid the expansion of the explosion impact in coalmine gob.     

Impact of a shock wave on a structure on explosion at altitude

The number of explosive attacks on civilian buildings has recently increased and the pattern of damage inflicted on structures when an explosion takes place at altitude remains quite difficult to predict. The primary aim of the work reported here was to enhance the understanding of how blast waves from an explosion at altitude interact with the ground and with a structure. Small-scale experiments were conducted using a propane–oxygen stoichiometric mixture as explosive. This approach is original because it models high-explosive detonation in terms of gaseous charge explosion using TNT equivalents. Several non-dimensional laws are expressed and validated by experiments. These relationships allow determination of the propagation of a blast wave and its interaction with a structure as a function of the position of the explosive charge when the explosion occurs at altitude. Then, from knowledge of the blast loading, using Hopkinson's scaling law and TNT equivalents, we can predict the interaction of blast waves with the ground and a structure on a real scale. Simulations were performed using the Autodyn code, and good correlation with the experimental results was obtained.     

采用火焰传感器的高速抑爆响应系统测试研究

为实现主动抑制瓦斯爆炸,研制了高速抑爆响应系统。选用尺寸为150mm×150mm×1 600mm的有机玻璃管道,在CH4体积分数为9.5%的条件下进行响应系统测试实验。系统采用火焰传感器进行爆炸火焰探测,通过所设计的程序自主判定瓦斯爆炸的发生并输出控制电信号,以继电器或MOS管为电路控制开关,通过电磁阀控制抑爆剂的喷出。实验结果表明,火焰传感器探测、信号采集、爆炸判断、输出电信号的总平均耗时为22ms,抑爆剂开始释放的平均时刻为59.8ms,抑爆剂释放到管道顶端的平均时刻为79.8ms。而爆炸火焰传播到达喷头所在1.0m处平均时刻为176.2ms。实验表明该系统具有高速主动抑爆响应功能和良好的稳定性、可靠性。     

矿井防爆门、盖自动封堵装置研发

煤矿井底发生煤尘瓦斯爆炸事故时产生的冲击波会冲开风井防爆门、盖,引起主风机风流短路,井底风流紊乱、通风系统瘫痪,导致毒害气体扩散、瓦斯积聚,引发二次爆炸。为了减少因此造成的损失,研发了一种在防爆门、盖被摧毁后能自动封堵的装置,通过感应防爆门盖的损毁信号控制充气动力设备对气囊折叠体进行充气,折叠体被充气弹出储藏硐室,沿支撑架构延展、膨胀并充满井筒横截面,实施对风井的密封,以维持灾后井底持续通风,降低灾害后果,为井底幸存人员的生存与自救提供有利条件。