Pressure drop · coefficient · discharge
Incompressible orifice flow
Inputs
User-entered dimensionless discharge coefficient from 0 through 1; this screen does not select it.
User-entered circular orifice diameter.
User-entered circular upstream pipe internal diameter; it must exceed the orifice diameter.
User-entered absolute or gauge pressure on a consistent basis.
User-entered pressure on the same basis as upstream pressure.
User-entered incompressible fluid density at the stated condition.
Results
Incompressible volumetric flow
7.6758
Mass flow
7.6758
kg/sOrifice mean velocity
3.9093
Stated pressure difference
20,000
Orifice / pipe diameter ratio
0.4902
—Q = CdA2√[2(p1−p2)/(ρ(1−β⁴))]; ṁ = ρQ; β = D2/D1
A first-pass number, not a code check, certification, or approval. Read the method and its limits below. What this is and is not.
Nearby: Hydrostatic pressure · Flow continuity · Pipe mean velocity · Bernoulli equation
Method
Formula, when it applies, and when it does not
Calculate incompressible volumetric and mass flow through a sharp-edged orifice-meter geometry using a discharge coefficient.
Q = CdA2√[2(p1−p2)/(ρ(1−β⁴))]; ṁ = ρQ; β = D2/D1
When
- Incompressible fluid
- User-entered discharge coefficient
- Steady pressure difference
- Circular pipe/orifice geometry
Don’t
- This is a steady incompressible pressure-drop screen with user-entered discharge coefficient and circular geometry. It excludes gases/compressibility, choked flow, cavitation, viscosity/Reynolds effects, non-Newtonian fluids, temperature change, pulsation, installation requirements, upstream/downstream disturbance, meter calibration, uncertainty, permanent pressure loss, and acceptance/compliance.
ISO 5167 — flow measurement by differential-pressure devices