UN-423: Liquid Vortex(water cut meter)


Calculates the uncertainty in observed volume, mass and standard volume flowrate for a liquid flow through a vortex meter. Line and standard densities and their uncertainties are performed by user-selected density referral calculations. Pressure, temperature, measured density and water cut uncertainties are determined using the technical specification for the transmitters selected from the integrated transmitter selection tool.


The General tab is used to enter information, which is saved along with the uncertainty calculation and included in reports which are generated.

The tabs used for inputting data and calculating the uncertainty in the individual components of the uncertainty can be seen along the top of the module window.

The report tab is only visible once the calculation has been run and will not be visible if any parameters are changed until the calculation has been run once more.



Pressure units

This section gives the option of entering the pressure as either an absolute value or as a gauge value with reference to atmospheric (barometric) pressure. If Absolute is selected inputs are required for Absolute pressure and Atmospheric pressure and if Gauge is selected inputs are required for Gauge pressure and Atmospheric pressure. This ensures that whichever is chosen both the gauge and Absolute pressure value is available to other sections of the module.

For example: the Density calculation tab may require an absolute pressure to perform an AGA 8 calculation and the Gauge pressure may be used for the pressure transmitter calculation.

Absolute pressure – the Atmospheric pressure = Gauge pressure



This is the measured temperature of the liquid stream.


This is the line pressure of the liquid passing through the stream.

Note: As described above, if Absolute is selected inputs are required for Absolute and Atmospheric pressure and if Gauge is selected inputs are required for Gauge and Atmospheric pressure.

The default value for Absolute Pressure is set to 1 standard atmosphere (1.01325 bar)

Densitometer pressure

This is the measured pressure from the densitometer.

Densitometer temperature

This is the measured temperature from the densitometer.


the density of the liquid flowing through the stream.

Water Cut

Percentage of water in the flow.


The outputs section shows the calculated flow rate and uncertainty taken from the Oil Vortex Meter tab and Net Oil flow rates tab.

Calculation Blocks

The following blocks are used within this uncertainty module:



Measured Density

Water Cut

Oil Vortex Meter

Net Oil Flow Rates