A second-order moment model of particles in dense gas-solid flow is proposed based on the kinetic theory of granular flow.The solid phase constitutive model is closed with the approximated third-order moment enclosure equation of particle velocity from the elementary transport theory.The boundary conditions of particles are proposed in considering the energy transfer and dissipations by collisions between the wall and particles.Flow behavior of particles is numerically simulated in a bubble fluidized bed,which indicates the distinct anisotropy behavior of the turbulent particles.Simulated particle velocities are in agreement with the measurements by Muller et al(2008) and Yuu et al(2001).Predicted second-order moment of velocity has the same trend as that of measurements.The calculated Reynolds stresses per unit bulk density agree with the measured data by Muller et al(2008) and with the fluctuating velocity of particles measured by Yuu et al(2001).
采用考虑颗粒脉动流动对气相湍流流动影响的大涡模拟(LES)研究气相湍流,采用直接模拟蒙特卡罗方法(DSMC)模拟颗粒间的碰撞。单颗粒运动满足牛顿第二定律,颗粒相和气相相间作用的双向耦合由牛顿第三定律确定,考虑超细颗粒间的van der Waals作用力。数值模拟垂直管内超细颗粒气固两相流动,对颗粒相速度、浓度以及团聚物流动过程进行分析。
