Abstract:

An equation-free multi-scale method was proposed for simulating two-phase gas-liquid separation processes. The method took the lattice Boltzmann (LB) model as the meso-scopic simulator. Only a small amount of evolutionary steps were needed during the calculation, and then the results obtained from the meso-scopic simulator were reasonably extrapolated by second-order telescopic projection to predict the results of follow-up evolutionary steps quickly and precisely. Thus multi-scale simulation of two-phase gas-liquid separation processes could be done. The details of phase separation were presented by comparing the numerical simulation results in terms of coexistence curves and spurious currents. The results showed that the macro-scale characteristics of phase separation could be quickly and accurately reflected by the proposed multi-scale simulation method, proving the accuracy and efficiency of the proposed method.

Key words: two-phase flow, gas-liquid separation, lattice Boltzmann method, coarse projective integration, multiscale, numerical simulation

摘要：

提出了一种用于模拟气液两相分离过程的免方程多尺度方法, 该方法以格子Boltzmann(LB)模型作为介观仿真器, LB模型进行少量演化步后运用二阶伸缩式投影方法对介观仿真器演化得到的结果进行有效的外推处理, 能够快速准确地获取后续演化步的结果, 从而实现对气液两相分离过程的多尺度模拟研究。对气液分离过程中饱和密度曲线和模型产生的伪速度大小的对比分析表明所提出的多尺度模拟方法能够快速准确地反映气液两相分离过程的宏观特性, 证明了所提方法的准确性和高效性。

关键词: 两相流, 气液分离, 格子Boltzmann方法, 粗粒化投影积分, 多尺度, 数值模拟