论文部分内容阅读
基于双流体方程和颗粒动力学理论的计算模型被广泛应用于流化床的气固两相流数值计算,高精度网格是其准确计算流动的必要条件。一些经典的微尺度阻力模型,其网格尺度决定其模拟结果的精度。亚格子过滤双流体模型是一种有效的适用于粗糙网格的计算模型,其包含的气固相间作用力和颗粒相应力本构方程是在高精度网格条件下,以微尺度双流体方程和颗粒动力学理论计算得到的气固流场为基础,对计算结果进行小尺度过滤后得出。使用亚格子过滤双流体模型替换基于颗粒动力学理论的双流体模型,针对同一物理问题,在不同网格尺度下进行了数值计算,结果表明此计算模型相比经典阻力模型具有较好的网格无关特性,并且和实验结果较为一致。同时也对颗粒动力学理论与之相结合进行了尝试,即仅使用亚格子过滤阻力模型,颗粒相应力仍然使用颗粒动力学模型,其计算结果的网格无关性及与实验值的吻合程度优于经典模型。
The computational models based on the dual fluid equations and the particle dynamics theory are widely used in the numerical calculation of gas-solid two-phase flow in a fluidized bed. The high-precision grid is a necessary condition for accurate flow calculation. Some of the classic microscale drag models whose grid dimensions determine the accuracy of their simulation results. The sub-grid filtration two-fluid model is an effective computational model applicable to rough grids. The included gas-solid interaction force and particle corresponding force constitutive equation are based on high-precision grid conditions, Equation and particle dynamics theory to calculate the gas-solid flow field is based on the calculation results obtained after the small-scale filtration. The two-fluid model based on the particle dynamics theory is replaced by the sub-lattice filtration two-fluid model, and the numerical calculation is carried out under different grid scales for the same physical problem. The results show that this model has a better grid than the classical resistance model Irrelevant characteristics, and more consistent with the experimental results. At the same time, we also try to combine the theory of particle dynamics with that of the particle filtration model. That is to say, using only the sub-lattice filtration resistance model, the particle-related forces still use the particle dynamics model. The grid independence of the calculated results and the coincidence with the experimental values In the classic model.