Air Differential Pressure to Flow Calculator

Air Flow Formula:

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

Discharge Coefficient (C):

Cross-sectional Area (A):

m²

Pressure Difference (ΔP):

Air Density (ρ):

kg/m³

Flow Rate (Q):

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1. What is an Air Differential Pressure to Flow Calculator?

Definition: This calculator determines the volumetric flow rate of air through an opening or restriction based on the pressure difference across it.

Purpose: It's used in HVAC systems, pneumatic systems, aerodynamics, and fluid dynamics applications to estimate air flow rates.

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 (m²)
\( \Delta P \) — Pressure difference (Pa)
\( \rho \) — Air density (kg/m³)

Explanation: The flow rate depends on the pressure difference, opening size, and air properties, with the discharge coefficient accounting for real-world flow characteristics.

3. Importance of Air Flow Calculation

Details: Accurate flow rate calculations are essential for designing ventilation systems, pneumatic controls, and any application involving air movement through ducts or orifices.

4. Using the Calculator

Tips: Enter the discharge coefficient (default 0.62 for sharp-edged orifice), cross-sectional area in m², pressure difference in Pascals, and air density (default 1.225 kg/m³ at sea level). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical discharge coefficient (C) value?
A: For sharp-edged orifices, it's typically 0.62. For well-rounded openings, it can approach 1.0.

Q2: How do I determine the cross-sectional area?
A: For circular openings, use \( A = \pi \times r^2 \) where r is the radius in meters.

Q3: What affects air density (ρ)?
A: Density changes with altitude, temperature, and humidity. Standard air density at sea level is 1.225 kg/m³ at 15°C.

Q4: Can I use this for liquids?
A: Yes, but use the correct density for the liquid and ensure the discharge coefficient is appropriate.

Q5: How accurate is this calculation?
A: It provides a theoretical estimate. Real-world factors like turbulence, viscosity, and exact geometry may affect actual flow rates.