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本文采用了基于有限元的虚拟区域法在亚颗粒尺度上对单个焦炭颗粒在大空间的下落运动燃烧过程进行了数值模拟。控制方程为低马赫数可压缩流动方程及相应的能量和组分守恒方程。基于虚拟区域法的思想将颗粒视为浸入在背景网格中的有限大小区域,在有限元方法的离散方程中引入拉格朗日乘子保证颗粒区域速度场的刚体运动以及能量和组分方程边界条件。各方程采用分离变量求解的分步方法求解。本文给出了焦炭颗粒沉降燃烧的计算结果,同时证明了虚拟区域法可用于亚颗粒气固燃烧模拟。
In this paper, a finite element-based virtual area method is used to simulate the combustion process of single coke particles in a large space in sub-particle scale. The governing equation is a low Mach number compressible flow equation and the corresponding conservation of energy and components. Based on the idea of virtual region method, particles are treated as the finite size region immersed in the background grid. The Lagrange multiplier is introduced into the discrete equation of the finite element method to ensure the rigid body motion of the velocity field in the particle region and the energy and component equations Boundary conditions. Each equation is solved by the step-by-step method of separating variables. In this paper, the calculative results of coke particle subsidence combustion are given. At the same time, it is proved that the virtual region method can be used to simulate subgranular gas-solid combustion.