【作者】 李江涛；

【导师】 喻健良；

【作者基本信息】 大连理工大学 ， 安全技术及工程， 2006， 硕士

【摘要】 火焰在微型通道内的传播与淬熄规律,是安全技术领域的一项重要课题。为了发展和完善微型通道内火焰传播与淬熄的学术研究,本文通过数值模拟对微型圆管内预混火焰的淬熄规律进行了系统而深入的研究。 基于均相反应流时均方程组、κ-ε湍流模型和EBU-Arrhenius燃烧模型,建立了均相湍流燃烧流动的理论模型。利用SIMPLEC算法,采用FLUENT软件对微型圆管内预混火焰的传播与淬熄情况进行了二维空间的数值模拟。 首先应用上述数学模型对60目多层丝网内的丙烷-空气预混火焰的传播过程进行了数值模拟,并与实验值进行了比较。计算值与实验值吻合良好,从而证明了应用上述数学模型模拟微型通道内预混火焰的传播过程具有合理性。 建立了微型圆管的几何模型并进行了网格独立性分析。 通过对微型圆管内预混火焰的传播过程的数值模拟,得出以下主要结论: （1）预混火焰在微型圆管中的传播具有三种情况:火焰不能通过、火焰滞留后不能通过和火焰滞留后通过。用化学反应速率和温度分布随时间的变化情况详细描述了预混火焰在微型圆管中传播的三种情况。并认为化学反应释放的热量没有及时被壁面吸收是火焰出现滞留现象的原因。 （2）得出了火焰速度、微管管径、预混气的初始温度与淬熄距离之间的关系。火焰速度越高、微管管径越大、预混气的初始温度越高,相应的淬熄距离越长,淬熄越困难。 （3）通过对丙烷-空气、甲烷-空气和乙炔空气预混火焰的淬熄性能的比较,发现同等条件下,反应活性越高,相应的淬熄距离越长,淬熄越困难。 （4）对微型圆管与平板狭缝的淬熄性能进行了比较,发现同等条件下,微型圆管散热面积比平板狭缝大,因而淬熄性能优于平板狭缝。 （5）在分析了大量数值模拟数据的基础上,总结出了火焰速度、微管管径、预混气初始温度与淬熄距离之间关系的经验公式。 （L_q+0.7）/（D-0.2）·V₀/（V+50）·T_q/(T_ini+T_a)=C 经验公式与计算值吻合良好,因而该经验公式适用于描述微型圆管内预混火焰的淬熄规律。更多还原

【Abstract】 The characteristic of propagation and quenching of flame in micro channel is one of important security technologies. To develop the study on the propagation of flame in micro channel, the quenching characteristics of premixed flame in tubules have been systemically investigated by numerical simulation.Based on the time-averaged equations of homogenous reaction flow, k - e turbulent model and EBU-Arrhenius combustion model, the theoretical model of homogenous turbulent combustion flow has been formed. The two-dimensional numerical simulations of the process of propagation and quenching of premixed flame in tubules have been carried out by the general CFD code FLUENT with SIMPLEC scheme.The process of propagation of propane-air premixed flame in 60M multi-layer wire-web has been simulated firstly, and numerical values are in good agreement with corresponding experimental values. So the validity has been proved using the turbulent mathematical model to simulate the process of propagation and quenching of premixed flame in tubules.The geometrical model of tubule has been formed, and the grid size sensitivity has been performed in FLUENT.The main conclusions of this paper through the numerical simulation of the propagation and quenching of premixed flame in tubules are as follows:(1) Premixed flame in tubules exhibit three kinds of behaviors, i.e., not-passing-through, not-passing-through-with-retardation and passing-through-with-retardation. These behaviors have been described in detail by the contours of rate of reaction and temperature at different time. The heat energy of reaction not being absorbed in time is the cause of flame retardation.(2) The relationships between the flame velocities, tubule diameters, initial temperatures and the quenching lengths are obtained. The quenching length increases with the increase of velocity, diameter and initial temperature.(3) The quenching characteristics in tubules are compared among the propane-air, methane-air and acetylene-air, and the conclusion is obtained that the quenching length increases with the increase of the reaction activity.(4) Comparisons of quenching characteristics between tubules and narrow channels are obtained. And tubules’ quenching characteristics are better in the same conditions.(5) Based on analyzing a large number of simulations, the experiential formula about the relationships between flame velocities, tubule diameters, initial temperatures and quenching lengths is obtained, and is in good agreement with numerical values.c D-0.2 K + 50 Tini+TaSo this experiential formula is applicable to describe the quenching characteristics of premixed flame in tubules.更多还原