【作者】 朱传杰；

【导师】 林柏泉；

【作者基本信息】 中国矿业大学 ， 安全技术及工程， 2011， 博士

【摘要】 _煤矿瓦斯爆炸事故是当前大多数采煤国家面临的重大灾害之一,它除了直接造成大量财产损失和人员伤亡外,还会诱发次生灾害的发生。本文研究了瓦斯爆炸冲击波扬尘特征及其诱发的气相冲击波和固相高速粒子耦合作用下的多相破坏效应,综合运用爆炸力学、化学反应动力学、多相流体力学、材料力学、岩石力学等多学科知识,进行了30多组实验、50多组数值模拟和大量理论分析,研究了该类灾害发生、发展的基本规律及其涉及到的关键科学问题。取得的主要创新性成果如下:研究分析了煤矿受限网络巷道系统内的瓦斯爆炸的基本物理和化学特征,给出了爆炸动压、反射波压力与爆炸超压之间的定量耦合关系,首次研究了巷道网络特征对瓦斯爆炸传播的影响,发现了爆炸冲击波的叠加会使爆炸超压值增大的现象。采用数值模拟的方法研究了爆炸冲击波的波前流场特征及其他特征参数的变化规律,发现了开口型系统的冲击波前最大流速和超压呈分段线性关系,爆炸前期两者呈反比关系u_gas=3573.9-12228.8△P_max,后期呈线性正比关系u_gas)=235.6+1510.1△P_max。发现了闭口型系统内存在冲击波振荡现象,这种振荡由FCW和FSW的反射波引起,并使得爆炸超压明显变高,根据振荡规律首次做出了爆燃冲击波和流场的振荡频谱图,并提出了闭口型系统内利用首次峰值超压和流速的关系来预测波前流速,以便衡量爆炸扬尘特征。采用E-E方法研究了爆炸冲击波的扬尘特征,获得的扬尘过程与国内外实验研究结果得到了很好的吻合。首次研究了对应于不同爆炸强度的流速对冲击波扬尘特征的影响,指出波前流场扬尘并非流速越高效果越好,爆炸发展初期是冲击波扬尘的最佳阶段,本次研究中得到的最佳扬尘流速在100～300m/s区间内（对应的爆炸超压在0.3MPa以内）。同时研究了沉积粉尘密度和粒径对爆炸扬尘的影响,发现沉积粉尘密度（1000～3000kg/m³）对扬尘特征影响较小,而粒径（20μm～0.3mm）对扬尘特征影响显著,粒径较小时,粉尘可以在巷道空间内得到较好的分散,形成的粉尘团簇的各粉尘层分布均匀。首次研究了爆炸冲击波扬尘诱发的冲击波和高速固相粒子耦合下材料的破坏效应,提出了在冲击波作用下材料内部的应力分布状态,以及高速固相粒子产生的附加应力σsolid计算方法。建立了多相破坏试验系统,研究了气相冲击波和高速粒子耦合下材料的破坏特征,并与单一气相冲击波的破坏特征进行了对比,发现在高速粒子的附加应力作用下爆炸破坏出现增强现象。研究结果对于煤矿瓦斯爆炸诱发的气相冲击波和高速固相粒子的耦合破坏作用的防治,奠定了理论基础,对今后矿用产品的设计和人员的防护具有重要的理论意义和实践价值。另外,相关研究成果发表论文14篇,其中EI已收录1篇,EI源刊4篇,EI待收录会议论文1篇,SCI投稿2篇。该论文有图71幅,表12个,参考文献165篇。更多还原

【Abstract】 Gas explosion in underground coal mines has been the most significant disaster in most mining countries. It not only directly causes substantial property damage and human casualties, but also can induce secondary disasters. The multi-phase destructive effect coupling gas explosion shock wave and high-speed dust particles which was induced by dust lifting behind shock wave was studied in this paper by more than 30 experiments, 50 numerical simulations and theoretical analysis integrating explosion, chemical reaction kinetics, multiphase fluid mechanics, material mechanics, rock mechanics, and other subjects. The occurrence of this kind of disasters and its key scientific issues were discussed. The main innovative achievements made are as follows:Gas explosion Chemistry and Physics in comfined mine network were discussed in detail. The relationship between dynamic pressure, reflected shock wave pressure and explosion overpressure was established. The effect of connetion type of tunnels on explosion propagation was studied for the first time. It was found that peak overpressure in parallel tunnels was higher that in normal ones. The flow field before shock wave and other parameters during explosion propagation were obtained by numerical simulations. The relationship between peak gas velocity and peak overpressure followed linear function. They were fitted well by equation: u_gas=3573.9-12228.8△P_max in the initial stage of explosion and by equation: u_gas=235.6+1510.1△P_max in the fininal stage. The shock wave oscillation obviously in confined tunnels was observed, which was induced by the relection of FCW and FSW. Oscillation of shock wave has lead to higer peak overpressure. Oscillation pectrogram plot of reflection wave and its relationship with arrival time was given by us for the first time. The correlation of first peak overpressure and peak gas velocity was suggested for the prediction of dust lifting beford shock wave.The E-E model was used to study the dust lifting process before shock wave. The dust lifting process obtained by this method was fitted well with experimental results by other researchers. The effect of gas velocity on dust lifting process was studied. It was found that the best results didn’t appear at highest gas velocity. The best dust lifting process was at the initial stage of gas explosion, whose gas velocity lies between 100 and 300m/s （corresponding peak overpressure was less than 0.3MPa）. A study on the effect of dust density on dust lifting found that dust density contributed less, but the dust diameter play an important role in dust lifting.The multi-phase destructive effect coupling gas explosion shock wave and high-speed dust particles which was induced by dust lifting behind shock wave was studied for the first time. The stress distribution in materials under shock wave and method for calculating stress, σsolid, caused by high-speed particals were described. Experimental apparatus was established to study the multiphase destructive effects. The comparision of destroy by gas explosion shock wave and multiphase destructive effects shows that the materials was destroyed more seriously because of the addinitional stress of high-speed particals.Present research findings might have important scientific and applicational significance for the prevention of multi-phase destructive effect coupling gas explosion shock wave and high-speed dust particles.In addition, 14 papers about research results were and will be published, in which one has been indexed by EI, four will be published in EI source journals, one will be indexed by EI in a conference paper and two have been submitted to SCI journals.There are 71 figures, 12 tables and 165 references in this thesis.更多还原