Large eddy simulation of a medium-scale methanol pool fire using the extended eddy dissipation concept
Large eddy simulation of a medium-scale methanol pool fire using the extended eddy dissipation concept
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DOI：
10.1016/j.ijheatmasstransfer.2013.11.010
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发表时间：
2014-03
影响因子：
5.2
通讯作者：
Zhibin Chen;J. Wen;B. Xu;S. Dembélé
中科院分区：
文献类型：
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作者：
Zhibin Chen;J. Wen;B. Xu;S. Dembélé
涡流耗散概念（EDC）扩展到大涡模拟（LES）框架以下相同的逻辑的湍流能量级联最初提出的Magnussen，但考虑到亚网格尺度湍流的独特作用。假设湍流能量级联在滤波器宽度“Δ”下存在一系列结构水平，其尺度从Kolmogorov尺度到积分尺度。总动能及其耗散率用亚网格尺度（SGS）量表示。假设无限快的化学反应，EDC中的过滤反应速率由Kolmogorov尺度下的精细结构与周围流体之间的湍流混合速率控制。在开源的FireFOAM求解器中实现了新扩展的EDC，并使用该求解器对直径为30.5 cm的甲醇池火灾进行了大涡模拟。通过与相应的实验数据比较，预测的热释放率，辐射分数，速度及其波动，温度及其波动，湍流热通量，SGS和总耗散率，SGS和总动能，时间尺度和长度尺度，达到合理的协议。
The eddy dissipation concept (EDC) is extended to the large eddy simulation (LES) framework following the same logic of the turbulent energy cascade as originally proposed by Magnussen but taking into account the distinctive roles of the sub-grid scale turbulence. A series of structure levels are assumed to exist under the filter width “Δ” in the turbulent energy cascade which spans from the Kolmogorov to the integral scale. The total kinetic energy and its dissipation rate are expressed using the sub-grid scale (SGS) quantities. Assuming infinitely fast chemistry, the filtered reaction rate in the EDC is controlled by the turbulent mixing rate between the fine structures at Kolmogorov scales and the surrounding fluids. The newly extended EDC was implemented in the open source FireFOAM solver, and large eddy simulation of a 30.5 cm diameter methanol pool fire was performed using this solver. Reasonable agreement is achieved by comparing the predicted heat release rate, radiative fraction, velocity and its fluctuation, temperature and its fluctuation, turbulent heat flux, SGS and total dissipation rate, SGS and total kinetic energy, time scales, and length scales with the corresponding experimental data.