Gas Flow Rate Through Orifice Calculator

Gas Flow Rate Formula (Compressible Flow):

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

Discharge Coefficient (C):

Orifice Area (A):

m²

Pressure Difference (ΔP):

Gas Density (ρ):

kg/m³

Expansion Factor (Y):

Gas Flow Rate (Q):

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1. What is a Gas Flow Rate Through Orifice Calculator?

Definition: This calculator estimates the volumetric flow rate of gas through an orifice using the compressible flow equation.

Purpose: It helps engineers and technicians determine gas flow rates in piping systems, ventilation, and process control applications.

2. How Does the Calculator Work?

The calculator uses the compressible flow formula:

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

Where:

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

Explanation: The equation accounts for the orifice geometry, gas properties, and compressibility effects.

3. Importance of Accurate Flow Calculation

Details: Proper flow rate estimation ensures system efficiency, safety in gas handling, and accurate process control.

4. Using the Calculator

Tips: Enter the discharge coefficient (default 0.62 for sharp-edged orifice), orifice area, pressure difference, gas density (default 1.2 kg/m³ for air at STP), and expansion factor (default 1.0 for incompressible approximation).

5. Frequently Asked Questions (FAQ)

Q1: What is the discharge coefficient (C)?
A: A dimensionless factor (typically 0.6-0.9) that accounts for energy losses and flow contraction through the orifice.

Q2: When should I adjust the expansion factor (Y)?
A: For high-pressure drops (ΔP/P₁ > 0.2) where gas compressibility becomes significant.

Q3: What's a typical gas density value?
A: Air at standard conditions is ~1.2 kg/m³. For other gases, use ρ = (molecular weight)×(P/RT).

Q4: How do I calculate orifice area?
A: For circular orifices, A = π×(diameter/2)². Ensure units are in meters.

Q5: What are the limitations of this calculation?
A: Assumes adiabatic, isentropic flow and may need correction for very high velocities or non-ideal gases.