障碍物对激波诱导沉积煤粉影响的数值模拟研究

发布时间：2018-04-25 22:37

本文选题：瓦斯煤尘爆炸 + 煤尘卷扬　；参考：《中北大学》2015年硕士论文

【摘要】：我国拥有丰富的石化能源，同时也是一个能源生产大国和消费大国。煤炭在我国的能源结构中长期占主导地位，并且在未来的一段时间内，依然是国家基础建设中非常重要的战略物资。本文运用理论分析和数值模拟仿真相结合的手段对煤尘爆炸机理和条件，以及障碍物对瓦斯爆炸卷扬沉积煤粉的影响进行了研究。主要研究内容是，建立瓦斯爆炸卷扬沉积煤粉直管道模型，从理论分析和模拟仿真两方面讨论了煤尘颗粒在冲击波作用下的运动过程；在置障条件下，分别对障碍物阻塞率、障碍物数量、障碍物间距对煤尘卷扬的过程进行了模拟仿真。通过数值模拟得出以下结论： (1)煤尘卷扬过程一共经历三个阶段：加速上扬阶段、减速阶段和气力输送阶段。上扬阶段煤尘云的左端会呈现弯曲的钩状，且几乎全部分布在管道模型的下半部分；减速阶段经历的时间比较短，煤尘云浓度较高，大部分煤尘没有参加反应；气力输送阶段的煤尘在水平方向上的速度快速增大，煤尘颗粒开始延管道传播，煤尘区被拉长。 (2)不同阻塞率的障碍物对煤尘颗粒的影响不同，阻塞率为50%和75%时对煤尘云分布状况的影响较为显著；障碍物阻塞率越大，，煤尘颗粒在水平方向上的输送距离越短；障碍物阻塞率为50%时对压力的增速影响最大。 (3)障碍物的数量越多，管道内峰值压力越大，到达峰值所经历的时间越短。多障碍物情况下，压力会出现来回震荡的现象。 (4)障碍物间距对峰值压力的影响较小，且6m时压力的变化规律与3m时压力的变化规律相比也没有明显的变化。
[Abstract]:China is rich in fossil energy, but also a large country of energy production and consumption. Coal has dominated the energy structure of our country for a long time, and in the future, it is still a very important strategic material in the national infrastructure construction. In this paper, the mechanism and condition of coal dust explosion and the influence of obstacles on coal powder deposited by gas explosion are studied by means of theoretical analysis and numerical simulation. The main research contents are as follows: the model of straight pipeline of coal powder deposited by gas explosion is established, and the movement process of coal dust particles under shock wave is discussed from two aspects: theoretical analysis and simulation. The process of coal dust hoisting is simulated by the number of obstacles and the distance between obstacles. The following conclusions are obtained by numerical simulation: 1) the coal dust hoisting process goes through three stages: accelerating rising stage, decelerating stage and pneumatic conveying stage. In the upward stage, the left end of coal dust cloud will be crooked, and almost all of it will be distributed in the lower half of the pipeline model, and the deceleration period will be relatively short, the concentration of coal dust cloud will be higher, and most coal dust will not participate in the reaction. The velocity of coal dust in the horizontal direction increases rapidly in the stage of pneumatic conveying, the coal dust particles begin to spread along the pipeline, and the coal dust area is elongated. (2) the influence of obstructions with different blocking rates on coal dust particles is different, when the blocking rate is 50% and 75%, the distribution of coal dust clouds is more significant, and the bigger the obstruction rate is, the shorter the transport distance of coal dust particles in horizontal direction is. The obstruction ratio of 50 has the greatest effect on the growth of pressure. 3) the more obstacles, the greater the peak pressure and the shorter the time to reach the peak. In the case of multiple obstacles, the pressure will oscillate back and forth. (4) the distance between obstacles has little effect on the peak pressure, and the change of pressure at 6m is not obvious compared with that at 3m.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD712.7;TD714.5

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