Mass of fluid

Density and bulk modulus calculation: mass of fluid

We consider some fluid at the pressure Patm and the temperature T0. All the air/gas is separated from the liquid (without vapor).

We consider a unit volume of liquid at Patm and T0 (unit volume assumption), then from the definition of the parameter “air/gas content” x (see section Air/gas content parameter), we can write:

This gives for the volume of air/gas at atmospheric pressure and 273.15 K:

The mass of the fluid can be computed at the pressure Patm and temperature T0:

Then we can write the mass of fluid as:

Equation 10: Mass of fluid

This relationship is valid for a unit volume of liquid and for any pressure P and temperature T.

The mass of air is very small compared with the mass of the unit volume of liquid but it is taken into account to respect mass conservation.

We obtain the mass for the liquid (without vapor) and for the total air/gas (free and dissolved):