共查询到19条相似文献，搜索用时 46 毫秒
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有风情况池火灾热辐射下的最小安全距离 总被引：4，自引：0，他引：4
防火间距是石油化工企业平面设计中的一个重要参数,开放环境下的火灾热辐射受大气稳定程度的影响.本文从计算流体力学角度出发,应用CFD(Computationsl Fluid Dynamics)软件Fluent,基于SCI爆炸火灾工程试验"Pool Fire A"的大气条件,对"有风情况下,直径为10 m的苯液池火灾"进行数值模拟,得出非绝热条件下,苯燃烧的峰温以及产物组分、池火灾对周围环境热辐射的空间分布.温度最高点在对称面y=0上,最高温度为1 478 K、火焰倾斜角度为32°(与竖直方向的夹角)、火焰高10.2 m.对于锰钢材料、内径为10 m苯储罐,2～3级风力情况下,相邻两储罐间最小安全距离在上风向为20 m,下风向为27 m.最后对模拟结果进行了分析. 相似文献
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文中用CFD技术对甲苯池火灾进行数值模拟,首先对甲苯火焰进行数值计算,得到在稳定的横向风条件下,甲苯燃烧的峰温、产物组分、瞬时速度等火焰特征参数以及其空间分布情况：火焰温度的最高点在对称面y=0上,最高温度为1778K,火焰倾斜角度为26°（与竖直方向夹角）,火焰高为22.5m。然后应用CFD软件F luent对池火灾进行热辐射模拟,模拟结果表明：对于锰钢材料、内径为20m甲苯储罐,稳态有风池火灾情况下,相邻两储罐之间安全距离在上风向为59m,下风向为72m。由于描述燃烧过程和湍流情况的数学物理模型还不太完善、对大气状况的简化等原因,结果偏保守,文中对此进行了分析讨论。此项研究为CFD技术研究碳氢化合物火灾的一个尝试。 相似文献
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池火灾热辐射的数值研究 总被引：9，自引：3，他引：6
通过列举储罐火灾事故,提出对池火灾进行研究的重要性.介绍目前池火灾国内外的研究现状及发展情况,描述池火灾燃烧特征和模型.应用化学流体力学基本定律,建立了描述池火灾过程的基本控制方程组,并根据适当的条件选择辐射模型.建立物理模型,做出合理假设,确定初始和边界条件,对池火灾热辐射过程进行数值模拟,得出火焰周围入射热流密度分布图,计算出相邻两罐之间的最小安全距离,应用于工程实际中,给防火间距的制定提供理论依据,计算结果定性合理. 相似文献
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为研究大型储油罐区池火灾温度、热辐射强度、流速、组分等燃烧特性参数在油罐外不同区域的变化规律,以10万m3原油储罐区为研究对象,构建罐区池火灾燃烧数学模型,运用计算流体动力学(Computational Fluid Dynamics,CFD)技术进行数值模拟研究.结果表明:整个火场温度大致呈锥形分布,火焰温度最高可达1... 相似文献
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热辐射的破坏准则和池火灾的破坏半径 总被引：10，自引：4，他引：10
热辐射破坏是发生在开放气环境中的池火灾的主要破坏机理。本文讨论了热辐射的破坏准则，提出预测池火灾破坏半径的方法，进行了数值模拟计算，分而和时纳了池火灾的基本规律 相似文献
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以某小型危险化学品储存企业为例,采用池火灾伤害数学模型,以二甲苯储罐发生泄露为例,根据不同的热辐射入射强度造成的设备损害和人员伤亡情况进行了计算和分析,得出了池火灾热辐射安全距离的要求。并根据企业特点提出了日常管理中的对策措施。 相似文献
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为寻找储罐池火灾救援中的最佳灭火位置,选择最优化的应急演练方案,通过Mudan模型,分析池火灾燃烧特性,计算大型池火灾不同条件下的热辐射范围和强度;以某化工园区的真实储罐数据建立三维仿真模型,完成池火灾燃烧过程中动态热辐射演化三维仿真效果。结果表明：在有风条件下,火焰会朝下风向偏移,火灾热辐射危害范围也会受到风力影响,对于上风向区域,火灾热辐射危害范围受到风力影响减小;对于下风向区域,火灾热辐射危害范围受到风力影响增大。 相似文献
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基于建筑防火隔离带的设计理念,研究了黄磷储罐临界安全距离的计算方法,将黄磷储罐火灾简化为罐内池火模型,通过理论计算和数值模拟黄磷储罐火灾周边热辐射分布,根据目标可燃物接受到的临界辐射通量是否大于或等于10 kW/m2来确定临界安全距离。研究表明：临界安全距离可通过火焰对目标可燃物接受到的临界辐射通量求得,且理论计算和数值模拟计算获得的临界安全距离基本一致。对于黄磷储罐火灾的防治具有一定的参考价值。 相似文献
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基于油罐火灾数值模拟的模型选取与分析 总被引：5，自引：3，他引：2
计算机模拟方法是当今研究油罐火灾发生、发展规律的重要手段.为此,从油罐燃烧的特点出发,搜集了当前最新的17种火灾模型,对比分析了它们的特点和适用范围,并筛选出7种适于模拟油罐火灾的模型:ALOFT-FT,FDS,CFX,FLUENT,PHOENICS,JASMINE和FIRE.通过对这些模型计算方法的进一步比较,分析了利用这7种模型模拟油罐火灾的优点和缺点.最后,提出了运用FDS模型模拟油罐火灾的优势,并用其进行了计算和分析,得到了满意的结果. 相似文献
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S. Vasanth S.M. Tauseef Tasneem Abbasi S.A. Abbasi 《Journal of Loss Prevention in the Process Industries》2013,26(6):1071-1084
Pool fires are the most common of all process industry accidents. Pool fires often trigger explosions which may result in more fires, causing huge losses of life and property. Since both the risk and the frequency of occurrence of pool fires are high, it is necessary to model the risks associated with pool fires so as to correctly predict the behavior of such fires.Among the parameters which determine the overall structure of a pool fire, the most important is turbulence. It determines the extent of interaction of various parameters, including combustion, wind velocity, and entrainment of the ambient air. Of the various approaches capable of modeling the turbulence associated with pool fires, computational fluid dynamics (CFD) has emerged as the most preferred due to its ability to enable closer approximation of the underlying physical phenomena.A review of the state of the art reveals that although various turbulence models exist for the simulation of pool fire no single study has compared the performance of various turbulence models in modeling pool fires. To cover this knowledge-gap an attempt has been made to employ CFD in the assessment of pool fires and find the turbulence model which is able to simulate pool fires most faithfully. The performance of the standard k–? model, renormalization group (RNG) k–? model, realizable k–? model and standard k–ω model were studied for simulating the experiments conducted earlier by Chatris et al. (2001) and Casal (2013). The results reveal that the standard k–? model enabled the closest CFD simulation of the experimental results. 相似文献
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Liquefied natural gas (LNG) has been largely indicated as a promising alternative solution for the transportation and storage of natural gas. In the case of accidental release on the ground, a pool fire scenario may occur. Despite the relevance of this accident, due to its likelihood and potential to trigger domino effects, accurate analyses addressing the characterization of pool fires of LNG are still missing.In this work, the fire dynamic simulator (FDS) has been adopted for the evaluation of the effects of the released amount of fuel and its composition (methane, ethane, and propane), on the thermal and chemical properties of small-scale LNG pool fire. More specifically, the heat release rate, the burning rate, the flame height, and thermal radiation, at different initial conditions, have been evaluated for pool having diameter smaller than 10 m. Safety distances have been calculated for all the investigated conditions, as well.Results have also been compared with data and correlations retrieved from the current literature. The equation of Thomas seems to work properly for the definition of the height over diameter ratio of the LNG pool fire for all the mixture and the investigated diameters.The addition of ethane and propane significantly affects the obtained results, especially in terms of radiative thermal radiation peaks, thus indicating the inadequacy of the commonly adopted assumption of pure methane as single, surrogate species for the LNG mixture. 相似文献
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Liquefied petroleum gas (LPG) is flammable and has risks of pool fires during its transportation, storage, and applications. The heat radiation by LPG pool fires poses hazards to individuals nearby and can lead to potential failures of ambient facilities. Due to the high costs and invasive nature of experiments for investigating large-scale pool fires, computational fluid dynamics (CFD) is employed in this study as the cost-effective and noninvasive method to simulate the process and analyze the characteristics of large hydrocarbon pool fires. Specifically, an experimentally validated 3-D CFD model has been built to simulate surface emissive power (SEP) and incident radiation of large-scale LPG pool fires with three different diameters and wind speeds. Steady-state simulations with P1 radiation and probability density function (PDF) combustion models were employed to obtain reliable data after the optimizations based on the comparisons with experimental data and empirical models. The comparison with benchmark experimental data demonstrates that the CFD model employed in this study can accurately predict the incident radiation of large LPG pool fires. A new SEP correlation is also proposed, which is specifically for LPG pool fires with a diameter between 10 m and 20 m. Additionally, the safe separation distances between LPG facilities and surrounded objects have been estimated based on the CFD simulation results. The high-resolution CFD model for large LPG pool fires in this work provides noninvasive and direct quantitative evidence to enhance the fundamental understanding on the safety of large LPG pool fires and can assist regulatory agencies in refining the safety limits in the cost-effective and time-saving manners. 相似文献
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Fire is the most commonly occurring major accident hazard in the chemical and process industries, with industry accident statistics highlighting the liquid pool fire as the most frequent fire event. Modelling of such phenomena feeds heavily into industry risk assessment and consequence analyses. Traditional simple empirical equations cannot account for the full range of factors influencing pool fire behaviour or increasingly complex plant design. The use of Computational Fluid Dynamics (CFD) modelling enables a greater understanding of pool fire behaviour to be gained numerically and provides the capability to deal with complex scenarios.This paper presents an evaluation of the Fire Dynamics Simulator (FDS) for predictive modelling of liquid pool fire burning rates. Specifically, the work examines the ability of the model to predict temporal variations in the burning rate of open atmosphere pool fires. Fires ranging from 0.4 to 4 m in diameter, involving ethanol and a range of liquid hydrocarbons as fuels, are considered and comparisons of predicted fuel mass loss rates are compared to experimental measurements.The results show that the liquid pyrolysis sub-model in FDS gives consistent model performance for fully predictive modelling of liquid pool fire burning rates, particularly during quasi-steady burning. However, the model falls short of predicting the subtleties associated with each phase of the transient burning process, failing to reliably predict fuel mass loss rates during fire growth and extinction. The results suggest a range of model modifications which could lead to improved prediction of the transient fire growth and extinction phases of burning for liquid pool fires, specifically, investigation of: ignition modelling techniques for high boiling temperature liquid fuels; a combustion regime combining both infinite and finite-rate chemistry; a solution method which accounts for two- or three-dimensional heat conduction effects in the liquid-phase; alternative surrogate fuel compositions for multi-component hydrocarbon fuels; and modification of the solution procedure used at the liquid-gas interface during fire extinction. 相似文献
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Fire accidents of chemical installations may cause domino effects in atmospheric tank farms, where a large amount of hazardous substances are stored or processed. Pool fire is a major form of fire accidents, and the thermal radiation from pool fire is the primary hazard of domino accidents. The coupling of multiple pool fires is a realistic and important accident phenomenon that enhances the propagation of domino accidents. However, previous research has mostly focused on the escalation of domino accidents induced by a single pool fire. To overcome the drawback, in this study, the failure of a storage tank under the coupling effect of multiple pool fires was studied in view of spatial and temporal synergistic process. The historical accident statistics indicated that the accident scenario of two-pool fires accounted for 30.6% in pool fires. The domino accident scenario involving three tanks is analyzed, and the typical layout of tanks is isosceles right triangle based on Chinese standard “GB50341-2014”. The thermal response and damage of a target tank heated by pool fires were numerically investigated. The volume of 500 m3, 3000 m3, 5000 m3 and 10000 m3 were selected. Flame temperature was obtained by FDS, and then was input onto the finite element model. The temperature field and stress field of target tanks were simulated by ABAQUS. The results showed that the temperature rise rate of the target tanks under multiple pool fires was higher than that under a single pool fire. The failure time of the tank under the coupling effect of multiple fires was lower than that under the superposition of multiple fires without the first stage. The stress and yield strength were compared to judge the failure of the target tank. The model of failure time for the tank under the coupling effect of pool fires was established. Through the verification, the deviation of this model is 4.02%, which is better than the deviation of 15.76% with Cozzani's model. 相似文献
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The paper presents the results of the validation of the developed pool evaporation model using literature and our own experimental data. The proposed model was used to examine the effect of wind velocity and pool sizes on the evaporation rate of volatile liquid (hexane). Contrary to the semi-empirical evaporation model widely used in hazard assessment, stronger dependence of evaporation rate on pool size at low wind speeds is obtained. 相似文献