Air Flow Rate Through an Orifice Calculator

Air Flow Rate Formula:

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

Discharge Coefficient (C):

Orifice Area (A):

m²

Pressure Difference (ΔP):

Air Density (ρ):

kg/m³

Air Flow Rate (Q):

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1. What is an Air Flow Rate Through an Orifice Calculator?

Definition: This calculator determines the volumetric flow rate of air through an orifice based on the orifice characteristics and pressure conditions.

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

2. How Does the Calculator Work?

The calculator uses the orifice flow equation:

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

Where:

\( Q \) — Volumetric flow rate (m³/s)
\( C \) — Discharge coefficient (dimensionless)
\( A \) — Cross-sectional area of the orifice (m²)
\( \Delta P \) — Pressure difference across orifice (Pa)
\( \rho \) — Density of air (kg/m³)

Explanation: The equation calculates flow rate based on energy conservation principles, accounting for flow contraction and friction losses through the discharge coefficient.

3. Importance of Orifice Flow Calculations

Details: Accurate flow rate calculations are essential for proper system design, efficiency optimization, and equipment sizing in ventilation, compressed air, and industrial processes.

4. Using the Calculator

Tips: Enter the discharge coefficient (typically 0.6-0.65 for sharp-edged orifices), orifice area, pressure difference, and air density (default 1.225 kg/m³ at sea level). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the discharge coefficient?
A: It's a dimensionless factor (0-1) that accounts for flow contraction and energy losses. Typical values range from 0.6 for sharp edges to 0.98 for well-rounded orifices.

Q2: How do I calculate orifice area?
A: For circular orifices, use \( A = \pi \times r^2 \) where r is the radius. For other shapes, use appropriate area formulas.

Q3: When would I adjust air density?
A: Adjust for high altitude (lower density) or elevated temperatures. Standard air density is 1.225 kg/m³ at 15°C and sea level.

Q4: What pressure units should I use?
A: The calculator uses Pascals (Pa). 1 psi = 6894.76 Pa, 1 bar = 100,000 Pa.

Q5: Is this only for air?
A: While designed for air, the same principle applies to other gases if you use the correct density value.