Burner Orifice Size Calculator
Sizing an Orifice From First Principles
Rather than scaling from a known reference, this calculator sizes a burner orifice directly from the standard orifice flow equation, useful when designing a fuel train from scratch rather than adjusting an existing one.
The Formula
Area = Flow / (Cd × sqrt(2 × Pressure Drop / Density))
Diameter is then found from the circular area formula; Cd (discharge coefficient) defaults to 0.62 for a sharp-edged orifice.
Worked Example
A target flow of 0.002 m3/s at 5,000 Pa pressure drop, fluid density 0.8 kg/m3:
Area ≈ 0.002 / (0.62 × sqrt(2 × 5000/0.8)) ≈ 12.9 mm2 (4.05 mm diameter)
How to Use This Calculator
- Enter the target Flow Rate in m3/s.
- Enter the available Pressure Drop in Pa and Fluid Density in kg/m3.
- Optionally adjust the Discharge Coefficient (defaults to 0.62).
- Select Calculate to get required orifice diameter and area.
Related Calculations
Need required pressure for an existing orifice instead? See the Burner Fuel Pressure Calculator, or check overall burner capacity in the Burner Capacity Calculator.