Defining the pressures of a fluid in a nanoporous, heterogeneous medium

We describe the thermodynamic state of a single-phase fluid confined to porous medium with Hill’s thermodynamics small systems, also known as nanothermodynamics. This way defining system thermodynamics, separate set control variables, may be useful for study transport in non-deformable media, where presently no consensus exists on pressure computations. For fluid, we observe that there are two pressures, integral and differential pressures. use molecular simulations investigate confirm nanothermodynamic relations representative elementary volume (REV). model face-centered cubic lattice solid spheres varying porosity, calculate density, fluid-solid surface tension, replica energy, pressure, entropy, internal energy.