【作者】 胡春明；

【导师】 喻健良；

【作者基本信息】 大连理工大学 ， 安全工程及技术， 2006， 硕士

【摘要】 现代工业中广泛应用阻火器阻止可燃气体在输运管网中爆炸灾害事故的发生,研究预混可燃气体火焰在阻火单元中的传播对阻火器的设计与应用具有重要意义。本文通过实验及数值模拟的方法研究了预混火焰在不同狭缝间距及壁面温度的平板狭缝结构中传播与淬熄,旨在对阻火器的设计和应用及可燃气体燃烧爆炸的防治等提供参考。 实验研究了丙烷/空气预混火焰在平板狭缝结构中的淬熄,得到了火焰传播速度、狭缝间距与淬熄长度的关系,为数值模拟工作提供更多的参考数据。 建立了模拟非稳态预混火焰在平板狭缝中传播的二维理论模型及控制方程组,利用通用计算流体力学软件Fluent进行了网格独立性分析,模拟了不同速度的丙烷/空气、甲烷/空气预混火焰在不同狭缝间距及不同壁面温度的二维平板狭缝中传播与淬熄,获得了在各种不同条件下火焰的淬熄长度,并与本文实验及文献中的实验数据进行了对比,取得了较为一致的结果,并在总结分析大量模拟数据的基础上得到了预混火焰在平板狭缝中传播与淬熄的规律: 对预混火焰在平板狭缝中的传播过程的温度及种组分浓度的变化规律进行了分析,发现了火焰在狭缝中传播与淬熄的不稳定过程; 研究了火焰速度、狭缝间距和壁面温度对火焰传播与淬熄的影响,获得了各种条件下预混火焰在平板狭缝中的淬熄长度,发现火焰速度越大,狭缝间距越大,狭缝壁面温度越高,淬熄长度越大,火焰越难淬熄,并且随着火焰速度和狭缝间距的增大,壁面温度的上升对淬熄长度的影响越来越明显; 获得了火焰传播速度、狭缝间距、壁面温度与淬熄长度之间的无量纲关系式: (Lq)/G·(V_o)/V·(T_q)/(T_w)=C找到了淬熄长度与影响淬熄各因素间的无量纲常数C,并作出了常数C算图,通过查找不同狭缝问距和壁面温度对应的常数C值,可方便算出不同火焰速度的淬熄长度。 本研究所得的预混火焰在平板狭缝中传播与淬熄的规律,火焰速度、狭缝间距、壁面温度与淬熄长度的无量纲关系式及无量纲常数C算图,能为阻火器的研究设计及工程应用提供参考,对爆炸抑制理论的完善和爆炸抑制技术的推广应用具有积极意义。更多还原

【Abstract】 The investigations into premixed flame propagating in flame arrester elements are quite important for design and application of flame arresters since flame arresters are widely used in combustible gas transport pipe network in industry to avoid disaster explosion. Aiming to provide theoretical references for deflagration suppression and the design of flame arresters, premixed flame propagating and quenching in narrow under different conditions are studied in this paper in experiment and numerical simulations.Propane/air premixed flame propagating and quenching in narrow channel are studied in experiment, and the relationships between the quenching distance with the flame velocity and channel gap are obtained. Meanwhile, these results can give more reference to the work of numerical simulations.Two-dimensional theoretical model for unsteady premixed flame propagating in parallel plane is built. After grid size sensitivity simulations are performed in Fluent, a general propose CFD code, propane/air and methane/air premixed flame with different velocity propagating in narrow channel under different channel gap and wall temperature parallel plane are simulated, and the quenching distances under different conditions are obtained. The numerical results are compared with the experiment in this paper and the literature. The data are consistent with each other, which indicate that the numerical method in this paper is feasible. According to the analysis of the mass numerical datas, the rules of premixed flame propagating and quenching in narrow channel are obtained.The change of temperature and species concentration is shown in detail, and the unstable phenomenon is found when premixed flame propagates in narrow channel.Special attention is devoted to the influence of flame velocity, channel gap and wall temperature to quenching distance. Quenching distances under different conditions are got. For any specific flame, when the flame velocity is small and the channel is narrow, the quenching length becomes smaller compared with the case of high inflow velocity and broad channel. The quenching length is larger for the higher temperature of wall at the same flame velocity and channel gap. The larger the flame velocity and channel gap, the more distinct the influence of the wall temperature on quenching length.The relationships between the quenching distance and flame velocity, channel gap, wall temperature are as follows,G V TwDimensionless constant C of these factors is uncovered. The abac dimensionless constant C is worked out. Quenching distance of different velocity can be easily calculated, according to dimensionless formula and constant C.The premixed flame propagating and quenching in narrow channel has been revealed and the rules of quenching, when flame propagating in narrow parallel channel, also have been given. The corresponding dimensionless relationships obtained can be useful for the design and application of the flame arrester. These studies have positive effect on the development of explosion suppression theory and the application of explosion suppression technology.更多还原