S-C single component multiphase LB model w/ C-S EOS


I ask advices about single component multiphase LB model.

I applied

1.Shan-Chen LB model for single component multiphase flow
2.Carnahan-Starling (C-S) EOS
→ to perform high density ratio (water/air)
3.Exact-difference method (EDM)

This code was validated with the Laplace test and contact angle test after reaching steady state. It worked very well. However, when I tried to perform the Capillary intrusion test (Washburn, 1921), the unphysical problem was arose. The position of interface was moved and intruding liquid lengths showed good agreement with the theoretical values. The problem was gas phase was compressed and the mass was decreasing. Inversely, liquid mass was increasing. Thus, I simulated various cases, gravity-driven drainage and capillary uptake, but mass of liquid was not increasing. Finally, I figured out when gas bubble or small amount of gas was trapped by liquid, they were disappeared. Anybody had simu-lated S-C single component multiphase flow with C-S EOS. Please let me know,

1.Nobody who applied S-C LB model with C-S EOS in their code has this problem.
→ if yes, I have to fix my code. This means not model but my code has big problem.
2.This unphysical problem is nature using S-C LB model with C-S EOS
→ if yes, I will apply other EOS model in my code to solve this unphysical problem.