Multi-Dimensional Flamelet Modelling for the LES of Pulverised Coal Flames

该项目的主要目标是发展固体燃料燃烧的大涡模拟（LES）的多维小火焰模型。该项目包括（a）小火焰模型本身的开发，（B）通过直接数值模拟（DNS）进行先验模拟和验证，（c）小火焰方法作为大涡模拟的亚网格模型的后验应用。第二个供资期将用于在两个技术上高度相关的方面改进（第一个供资期开发的）现有模式。我们将首先考虑废气再循环（EGR）的情况下，并开发一个火焰模型，占流之间的混合，其特征在于不同的反应进程，将是典型的EGR。然后，现有的火焰模型将被扩展，以准确地捕捉酸化污染物（NOx和SOx）及其前体的预测。这需要-作为先决条件-所有含氮和硫的燃料组分的热解的详细近似，并且这将通过实施用于固体燃料转化过程的动力学的成熟的PoliMi方法来实现。第二个供资期的最终成果将是一个经过验证的、用于EGR和污染物形成过程的多维火焰-LES模型，与现有的基于RANS的解决方案相比，该模型有望改善预测。

The primary objective of the proposed project is the development of multi-dimensional flamelet models for large-eddy simulation (LES) of solid fuel combustion. The project is composed of (a) the development of the flamelet model itself, (b) a priori simulation and validation by direct numerical simulation (DNS) and (c) a posteriori application of the flamelet method as a sub-grid model for LES. The second funding period will be used to improve the existing model (as developed during the first funding period) with respect to two technically highly relevant aspects. We will first consider cases with exhaust gas recirculation (EGR) and develop a flamelet-model that accounts for mixing between streams that are characterized by different reaction progress as would be typical for EGR. Then, the existing flamelet model will be extended to accurately capture the prediction of acidifying pollutants (NOx and SOx) and their precursors. This requires - as a precondition - a detailed approximation of the pyrolysis of all nitrogen and sulphur containing fuel components, and this will be achieved by the implementation of the well-established PoliMi-approach for the kinetics of the solid fuel conversion process. The final outcome of the second funding period shall be a validated, multi-dimensional flamelet-LES model for processes with EGR and pollutant formation that promises improved predictions when compared to existing RANS based solutions.