气固多相颗粒旋流流动特性的数值模拟

Numerical Simulation of Hydrodynamics of Binary Gas-particle Swirling Flows

为分析双组分颗粒气固旋流的流动特性,基于欧拉欧拉双流体气固单相湍流统一二阶矩模型(unifiedsecond-order moment,USM),构建考虑各向异性的双组分颗粒颗粒相间和气体双组分颗粒相间相互作用的气固多相二阶矩雷诺应力输运方程(multi unified second-ordermoment,MUSM)以及颗粒与气相脉动速度相关的本构关联方程。此模型完全考虑了颗粒与颗粒相之间的脉动速度的关联及其各向异性特征。用Sommerfeld(1992)试验结果检验经MUSM退化为USM的计算结果。双组分等直径重轻颗粒气固旋流模拟结果表明:模拟结果与实验结果吻合良好,因颗粒惯性和湍流扩散作用,双组分颗粒气固流动不同于单相气固流动。轴向气体颗粒脉动关联速度约为颗粒颗粒的2倍,切向和法向应力的分布被重新分配。

To analyze the hydrodynamics of binaryparticles gas-particle swirling flows, a binary-particles multiunified second-order moment （MUSM） Reynolds stress equation was developed on the basis of single second-order-moment（USM） turbulence model. In this model, particle-particle and gas-particle two-phase fluctuation velocity correlation transportation were presented and their anisotropic characters were fully taken into account. Swirling gas-particle flow experiments data（Sommerfeld et al. 1992） were used to validate the model using reducing model and code of the mono-disperse particle gas-particle flows. Numerical simulations were performed for the gas-binary particles mixtures turbulent flows. Simulated results of the binary-particles with the different density and the same diameter are in good agreement with experimental data. Binary mixture system has a unique transportation behavior with a stronger anisotropy due to particle inertia and multiphase turbulence diffusions. Fluctuation velocity correlation of axial-axial gas-particle is about twice larger than those of axial-axial particle-particle interaction. Moreover, both normal and shear Reynolds stress are both redistributed.