Compressibility of single-phase fluid with density and molar volume :
c_f = \frac{1}{\rho_f} \frac{\partial \rho_f}{\partial p} = -\frac{1}{V_{mf}} \frac{\partial V_{mf}}{\partial p} |
The multi-phase compressibility is a linear sum of its components.
[Compressibility] [Multi-phase compressibility]