What Is the Orifice Plate Flow Rate & DP Calculator?
An orifice plate is a thin plate with a hole placed in a pipe to restrict fluid flow, producing a differential pressure proportional to the square of flow velocity.
How Does the Orifice Plate Flow Rate & DP Calculator Work?
Computes beta ratio β = d ÷ D.
Computes orifice area and velocity of approach factor.
Calculates volumetric flow rate in m³/hr, US GPM, and mass flow in kg/s.
Orifice Plate Flow Rate & DP Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
Q = Cd × A × (1 ÷ √(1 - β⁴)) × √(2 × ΔP ÷ ρ)
Standard ISO 5167 orifice equation accounting for velocity of approach factor and differential pressure.
How to Use the Orifice Plate Flow Rate & DP Calculator
- Enter pipe and orifice bore diameters.
- Enter differential pressure in kPa.
- Read calibrated volumetric flow rate.
Step-by-Step Example Calculation
50mm Orifice in 100mm Line at 25 kPa Differential Pressure
Input Values:
pipeDiameterMm:100
orificeDiameterMm:50
differentialPressureKpa:25
dischargeCd:0.61
Understanding Your Result
Flow varies with the square root of differential pressure.
Factors That Affect the Result
- Upstream and downstream straight pipe run lengths and flow conditioners.
When Should You Use This Calculator?
- Calibrating differential pressure transmitters, steam metering, and chemical flow control.
Assumptions & Limitations
- Assumes sub-sonic liquid water flow with standard edge sharpness.
Frequently Asked Questions
Calculation Accuracy & Reference Note
ISO 5167-2 precision orifice standard.