Compute flow rate, beta ratio, and pressure drop. Switch units, compare scenarios, and download reports. See trends clearly with responsive charts and practical guidance.
The page stays in a single-column flow, while the input controls use a responsive three, two, and one column grid.
| Case | Fluid | Pipe Diameter | Orifice Diameter | ΔP | Density | Viscosity | Typical Use |
|---|---|---|---|---|---|---|---|
| Example A | Water | 150 mm | 75 mm | 25 kPa | 998 kg/m³ | 1.0 cP | General liquid metering line |
| Example B | Air | 100 mm | 50 mm | 8 kPa | 1.225 kg/m³ | 0.018 cP | Low-pressure gas flow check |
| Example C | Light Oil | 80 mm | 40 mm | 35 kPa | 850 kg/m³ | 12 cP | Viscous hydrocarbon service |
β = d / Dd is the orifice diameter and D is the pipe inside diameter.
A₂ = π d² / 4A₁ = π D² / 4.
ṁ = Cd · Y · A₂ · √( 2 ρ ΔP / (1 - β⁴) )Cd is discharge coefficient, Y is expansibility factor, ρ is density, and ΔP is differential pressure.
Q = ṁ / ρ
V₁ = Q / A₁V₂ = Q / A₂
Re = ρ V₁ D / μμ is dynamic viscosity.
Y = 1 - (0.41 + 0.35 β⁴) · ΔP / (k · P₁)P₁ and isentropic exponent k.
For final design, custody transfer, and code compliance, verify the exact coefficient and tapping standard required by your project documents.
Fill in pipe diameter, orifice diameter, and the shared length unit. The orifice must be smaller than the pipe.
Enter differential pressure, upstream pressure, density, and viscosity. Choose gas mode when compressibility matters.
Use auto estimate for a quick result, or type a custom discharge coefficient from tests or specifications.
Select volumetric and mass flow units that match your report, datasheet, or field comparison needs.
Press the button. The result section appears below the header and above the form.
Check the pressure-versus-flow graph, then export a CSV summary or generate a PDF report.
It estimates orifice plate mass flow, volumetric flow, beta ratio, Reynolds number, velocities, and a gas expansibility factor from the entered process data.
Yes. Liquid mode uses an incompressible assumption. Gas mode applies a simplified expansibility correction, so upstream absolute pressure becomes important.
Gas calculations need upstream absolute pressure to estimate the expansibility factor and the downstream pressure after the differential drop.
Use auto for quick studies. Use manual when your project standard, lab test, meter calibration, or vendor documentation gives a specific coefficient.
Many standard installations operate within a moderate beta range. Extreme values may increase uncertainty or installation sensitivity, so design checks matter.
Viscosity influences Reynolds number. Lower Reynolds number can shift the estimated discharge coefficient and change the predicted flow rate.
No. It is a practical engineering calculator for quick studies and reporting. Final design should follow your required standard and tapping arrangement.
It plots calculated flow against differential pressure around the entered operating point, helping you visualize sensitivity and operating range.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.