气粒流动两相亚网格尺度动能模型的大涡模拟

LARGE EDDY SIMULATION OF GAS-PARTICLE FLOWS USING A NEW TWO-PHASE SUB-GRID SCALE TURBULENCE MODEL

目前多数两相流动的大涡模拟采用单相流动的亚网格尺度应力模型,没有考虑或者没有完整地考虑两相亚网格尺度应力间的相互作用。本文提出一种两相亚网格尺度动能模型(LES-kkp),可以完整地考虑其相互作用。将该模型用于突扩气粒两相流动的大涡模拟,同时进行统一二阶矩(USM)两相湍流模型的雷诺平均模拟(RANS)。瞬态结果显示出两相流动中的气体形成了典型的拟序结构,但颗粒流动结构完全不同于气体的,没有形成涡结构。LES-kkp和RANS-USM模拟结果实验检验表明,对时间平均速度两种模拟给出结果与实验结果吻合良好,即RANS-USM得到了LES-kkp的验证。对两相均方根脉动速度和两相脉动速度关联量,LES-k-kp的模拟结果优于RANS-USM的模拟结果。

Presently, the most of single gas phase sub-grid scale stress model for large eddy simulation （LES） of gas-particle flows, where the sub-grid scale stress interaction between gas and particle phase are not or fully not considered. In order to make up recover, a new two-phase sub-grid scale （LES-kkp） turbulence model is proposed. Meanwhile, a unified second moment order two-phase Reynolds stress model （USM） for Reynolds averaged Navier-stokes （RANS） is carried out. The instantaneous flow structure that the typical coherent structure of gas phase flows is produced. But, particle phase is not formed the eddy structure. Both predicted two-phase time-averaged velocities are validated by measurement results and in good agreement with the experimental results. In other words, RANS-USM is verified by LES-kkp. On the gas-particle fluctuation velocity and its correlation terms, the LES predicted values are higher than the RANS modelling values.