立式天然气储罐泄漏扩散数值模拟研究

发布时间：2018-04-12 11:14

本文选题：立式储罐 + 储罐区　；参考：《江西理工大学》2015年硕士论文

【摘要】：天然气储罐因泄漏而引发火灾爆炸事故近年来频有发生,一旦此类事故发生将极有可能造成大量的财产损失和人员伤亡,不但严重威胁到人的生命安全同时也会对周围环境造成污染。对天然气储罐泄漏事故进行数值模拟研究,可以较好的掌握天然气储罐泄漏时的扩散路径以及天然气气云的分布规律,为天然气泄漏扩散的预防与控制提供一些必要的技术指导。本文运用流体力学软件Fluent对立式天然气储罐以及储罐区的泄漏事故进行了三维仿真模拟。对比分析风向、风速、泄漏口位置、泄漏口大小等因素对立式天然气储罐泄漏过程的影响。同时对比分析了储罐内部压强和储罐间距对储罐区内泄漏事故的影响。储罐在顺风泄漏的情况下,泄漏天然气会随风流快速扩散,不会在泄漏口的方向上堆积,气云内部浓度较低。逆风泄漏情况下,由于风流运动方向与天然气泄漏方向相反,此时风流对泄漏过程起到持续的阻碍作用,导致泄漏天然气大量堆积在储罐周围,且气云内部浓度较高。风速越大,会降低泄漏气云内部浓度。泄漏口位置越靠近地面,泄漏天然气越不易扩散,在泄漏口与地面之间聚集且浓度高。泄漏口口径增大,相同时间内泄漏而出的天然气越多,所形成的气云体积更大。储罐区内,罐内压强一定范围内增大或减小,对泄漏之后浓度在燃爆极限范围内的气云分布影响不大。储罐间距较大时,泄漏气云扩散距离更远,气云厚度越低。研究结果表明:在边界条件与基本假设的前提下,储罐逆风泄漏的危险性远大于顺风泄漏的情况。风速的增大会促进空气与泄漏天然气的融合,降低气云内部浓度,对泄漏事故的危险性有一定的缓解作用。泄漏口位置低,导致气云扩散空间减小,地面摩擦阻力也会抑制气云的扩散,导致浓度上升,危险性越大。泄漏口口径的大小会直接影响到事故发生之后的危险性。一定程度上增大或者降低储罐内部工作压强对降低事故发生之后的危险性并没有太大的作用。增大储罐之间的间距,会降低泄漏事故发生时所带来的危险性。
[Abstract]:Fire and explosion accidents caused by natural gas storage tanks have occurred frequently in recent years. Once such accidents occur, it is very likely to cause a large number of property losses and casualties.It is not only a serious threat to the safety of human life, but also to the surrounding environment pollution.The numerical simulation study on the leakage accident of natural gas storage tank can better grasp the diffusion path and the distribution law of gas cloud during the leakage of natural gas tank.To provide some necessary technical guidance for the prevention and control of natural gas leakage and diffusion.In this paper, Fluent software is used to simulate the leakage accident of natural gas storage tank and tank area.The effects of wind direction, wind speed, leakage location and leakage port size on the leakage process of natural gas storage tank are analyzed.At the same time, the effects of internal pressure and tank spacing on the leakage accident in the tank area are compared and analyzed.Under the condition of downwind leakage, the leaking natural gas will spread rapidly with the wind flow, and will not accumulate in the direction of the leak, and the concentration of the gas cloud will be lower.In the case of counterwind leakage, because the direction of wind flow is opposite to the direction of natural gas leakage, the wind flow plays a persistent role in hindering the leakage process, resulting in a large amount of leaking natural gas accumulation around the tank, and the concentration of gas cloud is relatively high.The higher the wind speed, the lower the internal concentration of the leaking gas cloud.The closer the leak is to the ground, the more difficult it is to spread the gas, and the higher the concentration is, the higher the concentration is between the leak and the ground.The larger the diameter of the leak is, the larger the volume of gas cloud is.In the tank area, the pressure in the tank increases or decreases in a certain range, which has little effect on the distribution of gas cloud in the limit range of explosion after leakage.When the tank spacing is larger, the leakage gas cloud diffuses farther and the gas cloud thickness is lower.The results show that under the premise of boundary conditions and basic assumptions, the risk of tank leakage is much greater than that of downwind leakage.The increase of wind speed will promote the fusion of air and natural gas leakage, reduce the concentration of gas cloud, and alleviate the risk of leakage accident.The lower the leak location, the smaller the gas cloud diffusion space, and the more dangerous the surface friction will be, which will restrain the gas cloud diffusion and lead to the increase of the gas cloud concentration.The size of the leak diameter will directly affect the risk after the accident.To a certain extent, increasing or reducing the internal working pressure of the tank has little effect on reducing the risk after the accident.Increasing the distance between tanks will reduce the risk of leakage accidents.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE88

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