Air Flow Rate Calculator From Pressure

Orifice Equation:

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

Discharge Coefficient (C_d):

dimensionless

Area (A):

m²

Pressure Drop (ΔP):

Density (ρ):

kg/m³

Flow Rate (Q):

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1. What is the Orifice Equation?

The orifice equation calculates fluid flow rate through an orifice based on pressure differential. It's widely used in fluid mechanics for measuring flow rates in pipes, ventilation systems, and various industrial applications.

2. How Does the Calculator Work?

The calculator uses the orifice equation:

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

Where:

\( Q \) — Flow rate (m³/s)
\( C_d \) — Discharge coefficient (dimensionless)
\( A \) — Cross-sectional area of orifice (m²)
\( \Delta P \) — Pressure drop across orifice (Pa)
\( \rho \) — Fluid density (kg/m³)

Explanation: The equation relates flow rate to the square root of pressure difference, accounting for energy losses through the discharge coefficient.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculation is essential for system design, performance monitoring, energy efficiency optimization, and ensuring proper operation of HVAC systems, pipelines, and industrial processes.

4. Using the Calculator

Tips: Enter discharge coefficient (typically 0.6-0.9 for sharp-edged orifices), area in square meters, pressure drop in Pascals, and fluid density in kg/m³. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical discharge coefficient value?
A: For sharp-edged orifices, C_d is typically 0.6-0.65. For well-rounded orifices, it can be 0.9-0.98.

Q2: Can this calculator be used for liquids?
A: Yes, the orifice equation applies to both gases and liquids, provided the correct density is used.

Q3: What are common applications of orifice flow meters?
A: HVAC systems, natural gas pipelines, water treatment plants, chemical processing, and compressed air systems.

Q4: What are the limitations of the orifice equation?
A: Assumes incompressible flow, requires fully developed flow profile, and may need correction for compressibility effects at high velocities.

Q5: How accurate is this calculation?
A: Accuracy depends on proper C_d selection and measurement precision. Professional installations typically achieve ±2-5% accuracy.