Numerical Simulation of Delft-Jet-in-Hot-Coflow (DJHC) Flames Using the Eddy Dissipation Concept Model for Turbulence-Chemistry Interaction
Numerical Simulation of Delft-Jet-in-Hot-Coflow (DJHC) Flames Using the Eddy Dissipation Concept Model for Turbulence-Chemistry Interaction
复制标题
DOI：
10.1007/s10494-011-9337-0
复制
发表时间：
2011-12-01
影响因子：
2.4
通讯作者：
Roekaerts, Dirk
中科院分区：
文献类型：
--
作者：
De, Ashoke;Oldenhof, Ernst;Roekaerts, Dirk
在本文中，我们报告的数值研究结果的湍流天然气燃烧的射流稀薄燃烧产物的同向流中的Delft-Jet-in-Hot-Plastlow（DJHC）燃烧器，模拟温和（中度和强烈的低氧稀释）燃烧行为。重点是评估的涡耗散概念（EDC）模型的性能，结合两方程湍流模型和化学动力学计划约20种（Correa机制和DRM 19机制）通过比较预测与实验测量。我们研究了两种不同的火焰条件对应于两个不同的氧水平（7.6%和10.9%的质量）在热的同向流，并为两个射流雷诺数（Re = 4,100和Re = 8,800）。不同湍流模型预测的平均速度和湍动能与实测数据吻合较好，模型预测值之间没有明显差异。Realizable k-k模型在雾沫夹带的预测中表现出较好的性能。EDC燃烧模型预测过早点火导致径向平均温度分布在太低的轴向距离处的峰值。然而，该模型正确地预测了实验观察到的上升高度随射流雷诺数的下降趋势。EDC模型的平均反应速率的详细分析和模型预测和实验之间的偏差的可能原因是低湍流雷诺数效应被确定。使用修改后的EDC模型常数可以避免过早点火的预测。结果是弱敏感的层流粘性和层流扩散通量的子模型。
In this paper, we report results of a numerical investigation of turbulent natural gas combustion for a jet in a coflow of lean combustion products in the Delft-Jet-in-Hot-Coflow (DJHC) burner which emulates MILD (Moderate and Intense Low Oxygen Dilution) combustion behavior. The focus is on assessing the performance of the Eddy Dissipation Concept (EDC) model in combination with two-equation turbulence models and chemical kinetic schemes for about 20 species (Correa mechanism and DRM19 mechanism) by comparing predictions with experimental measurements. We study two different flame conditions corresponding to two different oxygen levels (7.6% and 10.9% by mass) in the hot coflow, and for two jet Reynolds number (Re = 4,100 and Re = 8,800). The mean velocity and turbulent kinetic energy predicted by different turbulence models are in good agreement with data without exhibiting large differences among the model predictions. The realizable k-epsilon model exhibits better performance in the prediction of entrainment. The EDC combustion model predicts too early ignition leading to a peak in the radial mean temperature profile at too low axial distance. However the model correctly predicts the experimentally observed decreasing trend of lift-off height with jet Reynolds number. A detailed analysis of the mean reaction rate of the EDC model is made and as possible cause for the deviations between model predictions and experiments a low turbulent Reynolds number effect is identified. Using modified EDC model constants prediction of too early ignition can be avoided. The results are weakly sensitive to the sub-model for laminar viscosity and laminar diffusion fluxes.