Air Flow Orifice Size Calculator

Orifice Area Formula:

\[ A = \frac{Q}{C_d \times \sqrt{\frac{2 \times \Delta P}{\rho_{air}}} \times 448.83} \]

Flow Rate (Q):

GPM

Discharge Coefficient (C_d):

Pressure Drop (ΔP):

psi

Air Density (ρ_air):

lb/ft³

Orifice Area (A):

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1. What is an Air Flow Orifice Size Calculator?

Definition: This calculator determines the required orifice area for a given air flow rate through a restriction.

Purpose: It helps engineers and technicians design and analyze fluid flow systems, particularly in HVAC, pneumatic systems, and process engineering.

2. How Does the Calculator Work?

The calculator uses the orifice flow equation:

\[ A = \frac{Q}{C_d \times \sqrt{\frac{2 \times \Delta P}{\rho_{air}}} \times 448.83} \]

Where:

\( A \) — Orifice area (square feet)
\( Q \) — Volumetric flow rate (gallons per minute)
\( C_d \) — Discharge coefficient (dimensionless)
\( \Delta P \) — Pressure drop across orifice (psi)
\( \rho_{air} \) — Air density (pounds per cubic foot)

Explanation: The equation relates flow rate to the orifice area, accounting for fluid properties and flow characteristics.

3. Importance of Orifice Size Calculation

Details: Proper orifice sizing ensures accurate flow measurement, system efficiency, and prevents excessive pressure drops in fluid systems.

4. Using the Calculator

Tips: Enter the flow rate in GPM, discharge coefficient (default 0.62 for sharp-edged orifices), pressure drop in psi, and air density (default 0.075 lb/ft³ for standard air). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical discharge coefficient value?
A: For sharp-edged orifices, 0.62 is common. Values range from 0.6-0.9 depending on orifice geometry.

Q2: How does air density affect the calculation?
A: Higher density fluids require larger orifices for the same flow rate at a given pressure drop.

Q3: What units should I use for pressure drop?
A: The calculator uses psi (pounds per square inch) for pressure drop.

Q4: Can I use this for liquids other than air?
A: Yes, but you must adjust the density value accordingly for the specific fluid.

Q5: What's the significance of the 448.83 factor?
A: This converts units to maintain dimensional consistency (GPM to ft³/s and other unit conversions).