The numerical simulation of the supercritical fluid in nano-pores is a grand research challenge that has applications in shale gas extraction, CO2 sequestration and so on. The coupling of non-equilibrium dynamics (beyond the Navier-Stokes) and the complicated gas-surface molecular interactions make the problem very tricky. Some works on the application of LBM in this field were reported, although many fundamental physics are not well known.

For instances, the "wall-scaling" mean collision time is coupled with the traditional LBM; this approach only works in simple channels (flow between parallel plates) but does not work in complex porous media, even for the simple ideal rarefied gas. Also, most of the current LBM use the combined bounce-back and specular-reflection boundary condition, with the parameters determined from the diffuse boundary condition, however, recent works of Beskok clearly demonstrates that the tangential momentum accommodation coefficients is a function of pore radius...So many problems un-solved or attempted in a wrong way.

Personally I would suggest to look at the fundamental physics instead of just applying LBM to get some results which you do not know whether they're right or wrong.

Dr. Wu,

Thanks for your valuable suggestions. You have a deep insight into this problem. It’s very useful for me.

Dear Dr. Wu,

I have read some papers about LBM simulating shale gas flow recently. As we all know, the macroscopic dynamics of a fluid can be seen as the result of the collective behavior of microscopic particles in the system. The different particles interactions depend on the transport coefficients in Navier-Stokes equations.

LBM is usually treated as solver to solve the Navier-Stokes (N-S) equations. The N-S equations is suitable for supercritical fluid (SCF). Can we use the different transport coefficients in LBM to simulate the SCF flow?

Regards,

Ying Yin