Multiphase flow in porous media

zhou

I am trying to model liquid-gas flow in solid porous media by applying multiphase model (Eulerian model) in Fluent. Either gas or liquid could be primary phase. I got one question. (1). When i define the secondary phase, i find i have to specify the diameter. However, either gas or liquid is not existed as bubbles or droplets in porous media. It is like a mixture of them. So How do i solve this problem in Eulerian model? Thanks.