Orifice Flow Calculator - Precise Flow Rate and Reynolds Number Computation
Quickly and accurately calculate the flow rate through a sharp-edged orifice with this Orifice Flow Calculator. Enter your pipe and fluid parameters to determine the orifice flow rate, discharge coefficient, and Reynolds number. An efficient tool for engineers and professionals working with fluid systems and industrial processes.
Input Parameters
Results
Orifice Flow Rate
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Orifice Flow Coefficient
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Orifice Reynolds Number
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Assumptions:
- Discharge coefficient (Cd) is fixed at 0.611 for sharp-edged orifices
- Fluid is incompressible and Newtonian
- Flow is steady-state and fully developed
- Orifice plate is thin with sharp edges
- Pressure taps are located at standard positions (D and D/2)
- No significant pipe friction losses outside the orifice region
- Temperature effects on fluid properties are negligible
Calculation Methodology & Formulas
1. Orifice Flow Rate
The flow rate through an orifice is calculated using the incompressible flow equation:
Q = Cd × A × √(2ΔP / ρ)
- Q = Flow rate (m³/s)
- Cd = Discharge coefficient (≈ 0.61 for sharp-edged orifices)
- A = Orifice area = π × d² / 4 (d in meters)
- ΔP = Pressure drop across the orifice (Pa)
- ρ = Fluid density = Specific Gravity × 1000 kg/m³
2. Orifice Reynolds Number
The Reynolds number determines the flow regime through the orifice:
Re = (ρ × v × D) / μ
- Re = Reynolds number (dimensionless)
- v = Actual velocity through the orifice (m/s) = Q / A
- D = Orifice diameter (m)
- μ = Dynamic viscosity (Pa·s)
3. Discharge Coefficient (Cd)
For sharp-edged orifices:
- Cd ≈ 0.61 for high Reynolds numbers (turbulent flow)
- This calculator uses a fixed Cd value of 0.611, suitable for most engineering applications