Menu Flow Medium - SF Pressure Drop Help

To calculate pressure drops you need data of flow medium: Density and viscosity. In these databases you will find properties of many liquids and gases. Besides you can estimate properties.

Calculation of properties of water and steam according Industry Standard IAPWS-IF 97.
Calculations are possible within the range:
0 °C <= Temp. <= 800 °C at pressure (abs.) <= 1000 bar
800 °C < Temp. <= 900 °C bei pressure (abs.) <= 100 bar
I you want calculate water at normal air pressure input pressure value 1.013 bar.

Calculation of density and viscosity of water and steam in saturated condition. In saturated condition (saturated steam, saturated liquid) is the medium at boiling point.
Calculation according Industry Standard IAPWS-IF 97 within the range: 0 to 373 °C

Calculation of real gas properties of dry air (gaseous and liquid state) in the range from 60 to 2000 K up to 20000 bar. The values are calculated data. Small differences to reality are possible. If you want calculate air on athmospheric pressure please use as pressure 1.013 bar.

Calculation of real gas properties of humid air in the range from 0 to 200 °C up to 100 bar. The values are calculated data. Small differences to reality are possible. If you want calculate air on athmospheric pressure please use as pressure 1.013 bar.

Calculation of real gas properties of air in saturated condition (saturated steam and saturated liquid) in the range from 60 to 132 K.

Calculation of real gas properties of CO2 in the range from 216 to 1100 K up to 8000 bar. The values are calculated data. Small differences to reality are possible. If you want calculate CO2 on athmospheric pressure please use as pressure 1.013 bar.
Calculation of density according Span and Wagner, calculation of viscosity according Fenghour and Wakeham.

Calculation of real gas properties of CO2 in saturated condition (saturated steam and saturated liquid) in the range from 217 to 304 K.

In this database you will find data of diverse liquids. These data are measurements no calculated data. Values between two measurements you can interpolate.

In this database you will find data of various gases at different pressures and temperatures.

Viscosity:
The viscosity values are measured values at atmospheric pressure (1.013 bar).
In the range of 0.1 - 10 bar the viscosity is not dependent of pressure and is consequently not calculated
If the pressure is > 1.013 bar the changing of the viscosity is calculated with the formula of Gardner. The error could be 5 to 10% if the molecules are uncomplex.

Density:
The density values are calculated with the formula of Redlich-Kwong-Soave. The results are very exact for real gases also.

Critical temperature:
The critical temperature of a material is the temperature above which unique liquid and gas phases do not exist. As the critical temperature is approached, the properties of the gas and liquid phases become the same. Above the critical temperature, there is only one phase.

Calculation of density and viscosity of liquids, gases and mixtures.
In many cases are no measured values are available and have to be calculated. The calculated properties are approximate values. If you need very exact data you should use measured values.
If you need exact data from Water, Air etc. please use the separate menus.

You can here calculate refrigerants also.

The following errors are possible:

Gases
Density: Very exact calculation
Viscosity at atmospheric pressure: Max. 4% (more if you calculate polar moleculs)
Viscosity at pressure > atmospheric: 5 to 10% (more if you calculate complex moleculs)

Liquids
Density: Max. 3%
Viscosity: Very exact calculation

The following formulas are used to calculate the properties:

Gases
Density: Redlich-Kwong-Soave
Viscosity: Rother und Gardner

Liquids
Density: Modif. Racket-Gleichung, Chien-Hou Chang, Xingmin Zhao
Viscosity: Diverse log. formulas

The calculated properties are approximate values. If you need very exact data you should use measured values
The viscosity calculation of mixtures is an estimation.

The mixtures are calculated from the properties of the components acc. the following formulas:

Gases
Density: Amagat
Viscosity: Mixture formula

Liquids:
Density: Amagat
Viscosity: Arrhenius

You can calculate aqueous solutions in different concentrations at different temperatures. It's also possible to calculate solutions with more than one substance.

The calculated properties are approximate values. If you need very exact data you should use measured values.

If you input unrealistic concentrations or temperatures above the boiling point the program doesn't show an error message because the program doesn't calculate solubilities/boiling points! Boiling points of aqueous solutions you can calculate with our software Dampfdruck.

Calculation of properties of liquid refrigerants (Glycol, Glycerol, Ethanol...) at different temperatures and concentrations.

Calculation of density and viscosity of heat transfer oils within the range from 0 to 300 °C.

The calculated properties are approximate values. If you need very exact data you should use measured values.

In this database you will find your own properties for liquids.

You can create several databases (as example aromatic hydrocarbons, heat transfer oils) as Excel files. These files must saved in the program folder "user-liquids" so the software can find the data. Please have a look in the example files to arrange the data so the software can classify the properties of the liquids. You can create or edit the database files with your Excel- or OpenOffice-Software.

In this database you will find your own properties for gases.

You can create several databases (as example hydrocarbons, nitrogen oxides) as Excel files. These files must saved in the program folder "user-gases" so the software can find the data. Please have a look in the example files to arrange the data so the software can classify the properties of the gases. You can create or edit the database files with your Excel- or OpenOffice-Software.