双流体模型中人工扩散的影响数值分析

Numerical Analysis of the Effect of Artificial Diffusion Terms on Two-Fluid Model

研究了双流体模型中加入人工扩散项后不同扩散项系数对模拟的影响。对于竖直管的Water Faucet问题,逐步增加人工扩散系数后非物理振荡完全消除。对于水平管流动病态区域的工况,不采用扩散系数在中等精细度网格上计算的结果同实验比较吻合,但无法得到网格无关解。采用Water Faucet问题确定的人工扩散系数进行计算,水动力学不稳定性被抑制,液塞频率被低估。因此,人工扩散的量随不同流动条件发生变化,需要具体确定。

When artificial diffusion terms are introduced in two-fluid model,the effects of different artificial diffusion coefficients are studied.For vertical pipe Water Faucet problem,when the artificial diffusion coefficients are gradually increased,nonphysical oscillations can be eliminated.For horizontal pipe flow in ill-posed region,the calculated results without diffusion terms agree with experimental data but the mesh independent solution cannot be obtained. When the coefficients calibrated in Water Faucet problem are adopted,hydrodynamic instability is suppressed to some extent and slug frequency is underestimated.Therefore,the amount of artificial diffusion varies with different flow conditions and should be determined specially.