# C281 – ISO 5167 Venturi Calculations

## Description

This calculation can be set to calculate the flow rate through a Venturi based metering system, the differential pressure setting of the metering system or the Venturi throat size to use for specified flowing conditions.

## References

ISO 5167 – Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full

ISO TR 9464 – Guidelines for the use of ISO 5167

Kelton calculation reference C281

KIMS calculation reference K216

Kelton calculation C271 – ISO 5167 Venturi Mass Flow Calculation

Kelton calculation C273 – ISO 5167 Differential Pressure Calculations

Kelton calculation C274 – ISO 5167 Sizing Calculation

Kelton calculation C261 – Gas Flowrate Conversion from Qm

Kelton calculation C262 – Liquid Flowrate Conversion

## Options

### Solve for

- Flow rate
- Throat diameter
- Differential pressure

This option is used to select what kind of calculation the user wishes to implement.

The rest of the options that can be encountered in this calculation can be found in the calculations referenced above.

## Calculation

### Mass Flow Rate

The mass flow rate is calculated using the formula shown in C271. Further flow rate outputs, if required, are calculated using one of the flow rate converters using this value of mass flow rate.

### Throat Diameter

The Venturi throat diameter is calculated according to the process described in C274.

### Differential Pressure

The differential pressure is solved as described in C273.