方法对于大粘度差两相流的模拟

Simulation of Two phase Flow with Large Viscosity Difference by Lattice Boltzmann Method

摘要:

为了模拟具有大粘度差的两相流，对Boltzmann (LB)方法中的伪势多组分模型进行了改进.伪势模型将粒子作用力转化为速度形式，再将其引入离散的LB方程.改进模型把力的添加形式变为将力离散处理后，引入离散的LB方程中，以此提高数值计算的稳定性.该模型能够比原伪势模型得到更小的虚假速度和更大的粘度差.通过对沥青水的大粘度差两相流体和粘性指进现象的模拟，验证了改进模型的正确性和有效性.该模型具有较好的适用性，它能模拟的两相流体最大粘度差可达到4 510倍.

Abstract:

The pseudo potential multi component model in Lattice Boltzmann(LB) Method is improved to simulate two phase flow with large viscosity difference. In the pseudo potential model, the interparticle forces are turned into velocity form and introduced into the discrete LB equation. In the improved model, the interparticle forces are discretized and added to the discrete LB equation, which leads to the better numerical stability. The improved model can get smaller spurious velocity and larger viscosity difference than the pseudo potential model. Simulation of asphalt water two phase flow, which is with large viscosity difference, and fingering in a channel are carried out to validate the improved model. It has a good applicability for simulation of fluids with viscosity difference, and the maximal viscosity difference of two phase fluids is 4 510 times.