使用扩散模型数值模拟二维湍流气固两相流

SIMULATION OF TWO-DIMENSIONAL GAS-PARTICLE TWO-PHASE FLOW USING DIFFUSION FLUX MODEL

本文从描述多维湍流气固两相流的两流体模型出发,导出了计算湍流气固两相流中固体颗粒扩散速度的计算模型,进而基于在一维流场中颗粒的终端速度是重力加速度gi的函数,提出在多维流场中颗粒相处于一个修正的加速度场g'i的作用下,该修正的加速度g'i包含了包括重力在内的各种力的作用,这些力对颗粒的加速作用与重力对颗粒的加速作用没有区别。根据这种观点,提出了用于模拟多维湍流气固两相流的改进的扩散模型。本文使用改进的扩散模型对台阶后方的气固两相流进行了数值模拟,并将数值计算结果与实验结果进行了比较,结果表明,改进的扩散模型的预报结果与实验结果符合得相当好。

A modified diffusion flux model is presented for the analysis of two-dimensional turbulent gas-particle two-phase flow. In the modified diffusion flux model, the particle phase in multidimensional gas-particle two-phase flow behaves in a modified acceleration field g'i, which includes the effects of various forces imposed on the particles. It is argued that all the forces including the gravity have the same effects on the particle phase as the gravity. The modified diffusion flux model is used to simulate the gas-particle two-phase flow behind a vertical backward-facing step. The simulation results are compared with the experiments. The comparison indicates that the modified diffusion flux model can be used to analyze the gas-particle two-phase flow effectively.