Multiphase Fluid is a Fluid Mixture consisting of phases, each occupying its own space volume.
Each phase of the Multiphase Fluid is represented either by a pure substance or by a Fluid Mixture (see Multiphase Fluid vs Fluid Mixture).
Fluid Mixture is a sum of Fluid Components, which are pure chemical substances.
Fluid Mixture can stay as a single phase with Fluid Components sharing the same volume.
Under specific temperature and pressure conditions Fluid Mixture can develop few phases, each occupying its own space volume.
The Fluid Components of each phase are sharing the same space volume.
See Also
Natural Science / Chemistry / Chemical Substance / Mixture / Fluid Mixture
Natural Science / Physics / Thermodynamics / Thermodynamic system / Phase / Multiphase Fluid