Gas Flow Calculation Through Orifice

Orifice Flow Equation:

\[ Q = Y C A \sqrt{\frac{2 \Delta P}{\rho}} \]

Expansion Factor (Y):

Discharge Coefficient (C):

Orifice Area (A):

m²

Pressure Difference (ΔP):

Density (ρ):

kg/m³

Flow Rate (Q):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Orifice Flow Equation?

The orifice flow equation calculates the volumetric flow rate of a gas through an orifice plate. It accounts for the expansion of gas (Y factor), discharge coefficient (C), orifice area (A), pressure difference (ΔP), and gas density (ρ).

2. How Does the Calculator Work?

The calculator uses the orifice flow equation:

\[ Q = Y C A \sqrt{\frac{2 \Delta P}{\rho}} \]

Where:

\( Q \) — Volumetric flow rate (m³/s)
\( Y \) — Expansion factor (dimensionless)
\( C \) — Discharge coefficient (dimensionless)
\( A \) — Orifice area (m²)
\( \Delta P \) — Pressure difference across orifice (Pa)
\( \rho \) — Gas density (kg/m³)

Explanation: The equation accounts for the relationship between pressure drop and flow rate through a restriction, with correction factors for gas expansion and flow characteristics.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculation is crucial for designing and monitoring gas systems, including pipelines, process equipment, and ventilation systems.

4. Using the Calculator

Tips: Enter all parameters in consistent units. Typical values: Y ≈ 0.95-1.0, C ≈ 0.6-0.65 for sharp-edged orifices. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is the expansion factor (Y)?
A: Y accounts for gas expansion through the orifice. For incompressible flow (liquids), Y = 1. For gases, it depends on pressure ratio and specific heat ratio.

Q2: How do I determine the discharge coefficient (C)?
A: C depends on orifice geometry and Reynolds number. For standard sharp-edged orifices, 0.61 is commonly used as a first approximation.

Q3: What are typical orifice areas?
A: Orifice areas range from very small (mm²) for flow measurement to large (m²) for process applications.

Q4: Are there limitations to this equation?
A: The equation assumes steady, isentropic flow and may need adjustments for very high pressure ratios or non-ideal gases.

Q5: Can this be used for liquid flow?
A: Yes, with Y = 1. The equation is fundamentally the same for liquid flow through an orifice.