Towards comprehensive computational fluid dynamics modeling of pyrolysis furnaces with next generation low-NOx burners using finite-rate chemistry
Towards comprehensive computational fluid dynamics modeling of pyrolysis furnaces with next generation low-NOx burners using finite-rate chemistry
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DOI：
10.1016/j.proci.2008.06.048
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发表时间：
2009
影响因子：
11.1
通讯作者：
Q. Tang;M. Denison;B. Adams;David Brown
中科院分区：
文献类型：
--
作者：
Q. Tang;M. Denison;B. Adams;David Brown
本文回顾了一个基于CFD的反应流动程序，该程序用于模拟过程加热器/加热炉中与低/超低NOx燃烧器相关的复杂物理过程。该计算工具将湍流力学、气相燃烧化学以及辐射燃烧室内的传导、对流和辐射换热的影响耦合在一起。该代码使用自适应网格优化来捕获燃烧器附近的混合。它包括两个湍流燃烧模型--涡耗散概念模型和联合标量概率密度函数模型。这些模型允许有限速率化学，在本工作中由基于准稳态假设的简化机制来表示。为了提高反应源项的计算速度，采用了原位自适应制表算法。辐射换热计算采用离散纵坐标方法。在单燃烧器试验炉上进行了多次模拟，以验证该建模工具使用两种简化机制和两种湍流燃烧模型的能力。将计算结果与测量数据进行比较，以评估这些模型对CFD程序的精度和效率的影响。在模拟中，结合PDF模型和19种物种还原机制的情况在CO和NO预测中取得了最好的结果。虽然它的运行时间明显长于其他情况，但考虑到本研究使用的有限计算资源，该方法在工业应用中的前景仍然非常令人鼓舞。
This paper reviews a CFD-based reacting flow code designed to simulate the complex physics associated with low/ultra-low-NOxburners in process heaters/furnaces. The computational tool couples together the effects of turbulent fluid mechanics, gas-phase combustion chemistry, and conductive, convective, and radiative heat transfer within the radiant firebox. The code uses adaptive mesh refinement to capture near-burner mixing. It includes two turbulent combustion models—an Eddy Dissipation Concept model and a joint scalar Probability Density Function model. These models allow for finite-rate chemistry, which is represented by reduced mechanisms based on quasi-steady state assumption in this work. An in-situ Adaptive Tabulation algorithm is used to speed-up the computation of reaction source terms. The radiative heat transfer is calculated using a discrete-ordinates method. Multiple simulations were performed in a single burner test furnace to demonstrate the capability of the modeling tool using two reduced mechanisms and the two turbulent combustion models. The results are compared to measured data to assess the impacts of these models on the accuracy and efficiency of the CFD code. Among the simulations, the case combining the PDF model and a 19-species reduced mechanism achieved the best results in CO and NO predictions. Although its run-time was significantly longer than the other cases, the future of this approach in industrial applications is still very encouraging considering the limited computational resource used in this study.