【作者】 江丙友；

【导师】 林柏泉；

【作者基本信息】 中国矿业大学 ， 安全技术及工程， 2014， 博士

【摘要】 瓦斯爆炸事故是我国煤矿井下最严重的灾害事故之一，容易造成大量的人身伤亡和巨大的国家财产损失。为了从源头上防止瓦斯积聚，越来越多的煤矿加大了瓦斯抽采的投入，但是我国低浓度瓦斯的抽采量占有较大比重，在通过管道长距离输送至瓦斯利用端的过程中也存在着严重的安全隐患。考虑到瓦斯爆炸特征参数众多，其发展过程中可能会呈现特殊性和复杂性，因此需要研究巷道（或瓦斯输送管道）内瓦斯爆炸的多参数时空演化特征，继而开发新型抑爆设备，把瓦斯爆炸灾害控制在小的范围内。本文采用理论分析、数值模拟和实验研究等方法，研究了瓦斯爆炸超压及火焰瞬时速度与传播距离的耦合关系、瓦斯爆炸多参数的加速发展特征、瓦斯爆炸多参数的衰减特征、瓦斯爆炸防爆安全距离及防火距离等，以此为指导，开发了高压气固两相射流幕抑爆惰化技术及装置，并测试了抑爆装置的响应时间和抑爆效果。取得的主要创新性成果如下：基于一定假设条件建立了瓦斯爆炸强冲击波衰减后的超压、气流速度、冲击波传播速度与传播距离的耦合关系式，发现超压与传播距离和巷道断面积成反比，与瓦斯爆炸释放总能量成正比，而气流速度、冲击波传播速度均与传播距离和巷道断面积的平方根成反比，均与瓦斯爆炸总能量的平方根成正比。在一定实验条件下得到了充满燃料平直钢管内瓦斯爆炸火焰瞬时传播速度与传播距离的耦合关系式，发现火焰瞬时速度随着传播距离的增大而增大，但增大幅度逐渐减小。计算了各种初始温度、初始压力、初始球形火焰半径和瓦斯积聚体积量等条件下的瓦斯爆炸防爆安全距离及防火距离。揭示了这些因素对爆炸多参数衰减特征及防爆距离的影响规律，发现初始温度的增大导致最大超压、最大密度、最大气流速度和最大燃烧速率呈线性关系减小，最高温度和防火距离呈线性关系增大，防爆安全距离逐渐增大；初始压力的增大可使最大超压、最大密度和最大燃烧速率线性增大，对防爆安全距离的影响不存在明显规律性，对防火距离的影响可以忽略；初始球形火焰半径的变化对最大超压、最大密度、最高温度、最大气流速度和最大燃烧速率的影响小，对防爆安全距离的影响不存在明显规律性，对防火距离的影响可以忽略；瓦斯积聚体积量的增大导致最大超压、最大密度、最大气流速度、最高温度和防爆安全距离呈增大趋势变化，防火距离呈明显线性关系增大。采用氮气与ABC干粉灭火剂的混合物作为抑爆剂，开发了高压气固两相射流幕抑爆惰化技术及装置。装置的喷撒效率比国家标准AQ1079-2009规定的参考值提高了24.73%，ABC干粉喷撒完成时间缩短了20%，从传感器接受火焰信号到喷撒出最大质量干粉灭火剂的总时间缩短了24.86%，只要抑爆剂喷射口前方某一火焰传感器与触发火焰传感器得到的火焰到达时间差介于117~919ms之间，则抑爆成功。通过抑爆试验发现，喷撒氮气与ABC干粉对爆炸超压及火焰速度的抑制作用比较明显，超压降幅最高为76.7%，火焰速度降幅最高为100%；火焰熄灭的位置基本处于抑爆剂喷射口前后3m范围内，小于标准规定的6m；喷撒一次高压氮气与普通ABC干粉抑爆后，剩余抑爆剂的存在还可以抑制至少5次瓦斯爆炸的传播。气固两相射流幕抑爆技术的研发成功可以为煤矿井下巷道或瓦斯输送管道内的瓦斯爆炸隔爆抑爆提供一种新的技术途径，研究成果对防止瓦斯爆炸灾害事故的扩大具有十分重要的科学价值和实际意义。更多还原

【Abstract】 Gas explosion is one of the most serious disasters in the coal mining accidents,and it can cause a large number of losses of human lives and property. More and moreinputs to gas drainage have been made in order to prevent gas aggregation at source.But in China, the amount of low concentration coal mine gas drainage accounts for alarge proportion, the serious safety hazards still exist in the process of gastransmission by long distance pipelines. Considering the parameters of a gasexplosion are multiple, the gas explosion propagation may present some particularitiesand complexities. So it is necessary to study on the multiparameter temporal andspatial evolution of gas explosions in roadways (or gas transmission pipelines), thento develop a new explosion suppression equipment which may control the gasexplosion disasters in a small area.In this paper, the methods of theoretical analysis, numerical simulation, andexperimental research were used to study on the coupling relationships of the gasexplosion overpressure and the flame instantaneous speed respectively with thepropagation distance, the multiparameter acceleration and attenuation characteristicsof gas explosions, and the explosion-proof safety distance and flameproof distance ofgas explosions. Based on these above, the active explosion suppression and inertingdevices using high-pressure gas-solid jet curtain were developed, and their responsetime and explosion-suppression effectiveness were also tested. The main innovativeresults are shown as follows.Based on some assumptions, the formulae for the coupling relationships of theoverpressure, the gas velocity, and the shock-wave propagation speed respectivelywith the propagation distance after the strong shock wave of a gas explosionattenuated were established. It was found that the overpressure was inverselyproportional to the propagation distance and the roadway cross-sectional area, anddirectly proportional to the total energy of the gas explosion. However, the gasvelocity and the shock-wave propagation speed were both inversely proportional tothe square root of the propagation distance and roadway cross-sectional area, and bothdirectly proportional to the square root of the total energy of the gas explosion. Undersome experimental conditions, the formula for the theoretical coupling relationshipbetween the flame instantaneous speed of a gas explosion occurred in a straight steelpipe filled with fuel and the propagation distance was built. It was found that the flame instantaneous speed increased with increasing distance from the ignition source,but the increasing amplitude gradually decreased.The explosion-proof safety distances and the flameproof distances of gasexplosions for various initial temperatures, initial pressures, initial spherical flameradii, and fuel volumes were calculated, and the influences of these factors on themultiparameter attenuation characteristics and explosion-proof distances of gasexplosions were also revealed. It was found that increasing initial temperaturedecreased the maximum overpressure, the maximum density, the maximum gasvelocity, and the maximum combustion rate linearly, increased the maximumtemperature and the flameproof distance linearly, and increased the explosion-proofsafety distance gradually. Increasing initial pressure increased the maximumoverpressure, the maximum density, and the maximum combustion rate linearly, butits effect on the explosion-proof safety distance had no obvious regularity and theeffect on the flameproof distance could be ignored. The effect of changing the initialspherical flame radius on the maximum overpressure, the maximum density, themaximum temperature, the maximum gas velocity, and the maximum combustion ratewas small, had no obvious regularity on the explosion-proof safety distance and couldbe ignored on the flameproof distance. Increasing fuel volume increased themaximum overpressure, the maximum density, the maximum gas velocity, themaximum temperature, and the explosion-proof safety distance, and increased theflameproof distance linearly.The explosion suppression and inerting devices using high-pressure gas-solid jetcurtain were developed, and the explosion suppressant was the two-phase mixture ofnitrogen and ABC dry powder. The spurt efficiency increased24.73%than thereference value setting by national standard AQ1079-2009, the spurt completion timeshortened by20%, and the total time from accepting flame sensor signal to spurtingthe maximum quality of ABC dry powder decreased by24.86%. If the difference offlame arrival time between the flame sensor in front of spurting powder position andthe trigger flame sensor was in117~919ms, the explosion suppression would besuccessful. By explosion suppression experiments, it was found that spurting nitrogenand ABC dry powder had an obvious suppression effect on the explosion overpressureand the flame speed, and the maximum decreasing amplitudes of overpressure andflame speed were76.7%and100%respectively. The flame extinction position waswith the scope of3m around the position of spurting explosion suppressant, less than 6m referred to the national standard. After the high-pressure nitrogen and ABC drypowder had suppressed the gas explosion propagation successfully, the surplusexplosion suppressants would still prevent at least five gas explosions. The successfuldevelopment of the explosion suppression technology using gas-solid two-phase jetcurtain might provide a new technical way for the isolation and suppression of gasexplosions in underground roadways of coal mines or the gas transmission pipelines.Research results might have very important scientific value and practical significanceon preventing the expansion of gas explosion disasters.更多还原