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Orifice Plate Flow Calculator

Calculate flow rate through an orifice plate using ISO 5167 differential pressure method.

Inputs
Enter your values below

0.6 typical for sharp-edged orifice

Result
Flow Rate
—
Enter values and click Calculate
Formula
c × (π × orifice_d² ÷ 4) × √(2 × dp ÷ (density × (1 − (orifice_d ÷ πpe_d)⁴))) × 3600
Result unit: m³/h

Q = Cd × A_orifice × √(2ΔP/(ρ(1−β⁴))) where β = d/D. Engine converts mm→m and kPa→Pa. ×3600 to m³/h.

Introduction

Calculate flow through a sharp-edged orifice plate per ISO 5167. Uses the discharge coefficient method where β = d/D and Cd ≈ 0.6 for thin-plate sharp-edged orifices at Reynolds numbers above 10,000.

Calculation Example

50mm orifice in 100mm pipe (β=0.5) at 10 kPa ΔP, Cd=0.6: ~20 m³/h water flow.

Inputs: c=0.6, orifice_d=50, pipe_d=100, dp=10, density=1000
Result: 19.6 m³/h

Engineering Applications

  • •Flow measurement
  • •Process control
  • •Custody transfer
  • •Pump performance testing

Frequently Asked Questions

What beta ratio is recommended?

ISO 5167 recommends β = 0.2-0.75. β = 0.4-0.6 gives best accuracy with acceptable pressure loss.

What permanent pressure loss does an orifice cause?

Permanent loss ≈ (1−β²) × ΔP ≈ 60-90% of measured differential. This is the main drawback vs venturi (10-20% loss).

Related Calculators

Flow Rate CalculatorPipe Flow CalculatorPressure Drop Calculator (Darcy-Weisbach)

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Disclaimer: Calculations are for reference and educational purposes only. Always verify results independently for engineering design. See full disclaimer.