What Is the Venturi Tube Flowmeter & Differential Pressure Calculator?
A Venturi meter is an inline differential pressure flow device invented by Giovanni Battista Venturi and Clemens Herschel in 1887.
How Does the Venturi Tube Flowmeter & Differential Pressure Calculator Work?
Incompressible fluids accelerate through a convergent cone, causing static pressure to convert into kinetic dynamic pressure.
Venturi Tube Flowmeter & Differential Pressure Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
Q = C_d \cdot A_2 \cdot \sqrt{\frac{2 \Delta P}{\rho \cdot (1 - \beta^4)}}, \quad \beta = \frac{d_2}{d_1}
Flow rate Q is calculated from throat area A2, diameter ratio beta, pressure drop delta P, and fluid density.
How to Use the Venturi Tube Flowmeter & Differential Pressure Calculator
- Input pipe inlet and throat diameters in mm.
- Specify measured differential pressure across pressure taps in kPa.
- Enter fluid density.
Step-by-Step Example Calculation
Water Pipe 100mm to 50mm Constriction
Input Values:
pipeInletDiameterMm:100.0
throatDiameterMm:50.0
pressureDropKpa:25.0
fluidDensityKgM3:1000.0
Worked Steps: At 25 kPa differential pressure, the Venturi meter passes 51.57 m³/hr (859.6 L/min / 227 GPM) at throat velocity 7.30 m/s.
Understanding Your Result
Volumetric Flow Rate: Delivered flow in m³/hr, L/min, and US GPM.
Throat Velocity: Speed of fluid rushing through constriction.
Mass Flow Rate: Flow in kg/s.
Factors That Affect the Result
- Beta diameter ratio, discharge coefficient Cd, and fluid density.
When Should You Use This Calculator?
- Municipal water distribution main metering, wastewater effluent conduits, and chemical refining pipelines.
Assumptions & Limitations
- Assumes steady, single-phase, incompressible liquid flow without cavitation boiling at the throat.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard ISO 5167 closed-form analytical flow calculation.