Physical properties of fluid and fluid transport in piping system
Density, specific volume, specific gravity
Density of fluid, compressibility of gas
Flow in pipes and valves theory - full content
The density is the mass of substance per unit of volume.
where is:
- &rho - density
- m - mass
- V - volume
The unit of density is kilogram per cubic meter [kg/m3] in SI system of units and used symbol is &rho .
Also, other units are used for density like gram per cubic centimeter [g/cm3], or gram per milliliter [g/ml]
which are both equal to 1000 kilograms per cubic meter [kg/m3].
For ideal gas relation between pressure, density and temperature is expressed using the equation of state:
where is:
- p - pressure
- &rho - density
- R - gas constant
- T - absolute temperature
For real gas modified equation of state is used with compressibility factor included:
where is:
- p - pressure
- &rho - density
- T - absolute temperature
- Z - compressibility factor
- R - gas constant
Compressibility factor is function of pressure and temperature. Compressibility factor can be
calculated using Berthelot equation:
where is:
- pr - reduced pressure
- Tr - reduced temperature
- Z - compressibility factor
which are calculated as follows:
where is:
- pc - critical pressure
- Tc - critical temperature
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