Abstract

In simulating two-phase combustion, most Reynolds-averaged Navier–Stokes (RANS) simulation and large-eddy simulation (LES) used Eulerian–Lagrangian (E–L) modeling (Eulerian treatment of gas phase and Lagrangian treatment of particles/droplets) which needs much more computational time than the Eulerian–Eulerian (E–E) or two-fluid modeling. However, in the E–E modeling, the problem of how to reduce the computation time for poly-dispersed particles is encountered . To solve this problem, the present author proposed an Eulerian–Eulerian–Lagrangian (E–E–L) modeling of two-phase combustion for both RANS modeling and LES. The E–E–L modeling is an Eulerian treatment of gas phase and a combined Eulerian–Lagrangian treatment of particles/droplets, in which the particle velocity and concentration are solved by Eulerian modeling, and particle temperature and mass change due to reaction are solved by Lagrangian modeling. In this paper, a review is given for an E–E–L modeling of coal combustion, its application in RANS simulation and its possible application in LES. For E–E–L LES, an energy equation model of two-phase sub-grid scale (SGS) stresses accounting for the interaction between two-phase SGS stresses is suggested, and a second-order moment SGS (SOM-SGS) turbulence-chemistry model is adopted to simulate gas-phase reaction in two-phase combustion. These SGS models were separately assessed by comparison with experiments.

Graphic abstract

中文翻译：

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两相燃烧的欧拉-欧拉-拉格朗日模型

摘要

在模拟两相燃烧时，大多数雷诺平均纳维-斯托克斯（RANS）模拟和大涡模拟（LES）使用欧拉-拉格朗日（E-L）建模（气相的欧拉处理和颗粒/液滴的拉格朗日处理）与欧拉-欧拉 (E-E) 或双流体建模相比，它需要更多的计算时间。然而，在E-E建模中，遇到了如何减少多分散粒子的计算时间的问题。为了解决这个问题，作者提出了适用于 RANS 模型和 LES 的两相燃烧的欧拉-欧拉-拉格朗日 (E-E-L) 模型。E-E-L模型是气相的欧拉处理和粒子/液滴的欧拉-拉格朗日组合处理，其中粒子速度和浓度通过欧拉模型求解，反应引起的颗粒温度和质量变化通过拉格朗日模型求解。本文对煤燃烧的 E-E-L 模型、其在 RANS 模拟中的应用以及在 LES 中的可能应用进行了综述。对于 E-E-L LES，建议采用两相次网格尺度 (SGS) 应力的能量方程模型来解释两相 SGS 应力之间的相互作用，以及二阶矩 SGS (SOM-SGS) 湍流-采用化学模型模拟两相燃烧中的气相反应。通过与实验比较来分别评估这些 SGS 模型。建议考虑两相次网格尺度（SGS）应力之间相互作用的能量方程模型，并采用二阶矩SGS（SOM-SGS）湍流化学模型来模拟气体两相燃烧中的相反应。通过与实验比较来分别评估这些 SGS 模型。建议考虑两相次网格尺度（SGS）应力之间相互作用的能量方程模型，并采用二阶矩SGS（SOM-SGS）湍流化学模型来模拟气体两相燃烧中的相反应。通过与实验比较来分别评估这些 SGS 模型。

图文摘要