Air Flow Rate Calculation Using Pressure

Orifice Flow Equation:

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

Discharge Coefficient (C_d):

dimensionless

Area (A):

m²

Pressure Difference (ΔP):

Density (ρ):

kg/m³

Flow Rate (Q):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Orifice Flow Equation?

The orifice flow equation calculates the volumetric flow rate of a fluid through an orifice based on pressure difference, fluid density, orifice area, and discharge coefficient. It's widely used in fluid mechanics and engineering applications.

2. How Does the Calculator Work?

The calculator uses the orifice flow equation:

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

Where:

\( Q \) — Volumetric flow rate (m³/s)
\( C_d \) — Discharge coefficient (dimensionless)
\( A \) — Cross-sectional area of orifice (m²)
\( \Delta P \) — Pressure difference 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 designing fluid systems, sizing pipes and valves, process control, and optimizing energy efficiency in industrial applications.

4. Using the Calculator

Tips: Enter discharge coefficient (typically 0.6-0.8 for sharp-edged orifices), area in square meters, pressure difference in Pascals, and fluid density in kg/m³. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for discharge coefficient?
A: For sharp-edged orifices, C_d is typically 0.6-0.65. For rounded orifices, it can be 0.8-0.98 depending on geometry.

Q2: Can this equation be used for compressible fluids?
A: This form is for incompressible fluids. For compressible fluids like gases at high velocities, additional compressibility factors are needed.

Q3: What are common applications of orifice flow meters?
A: Orifice plates are widely used in industrial flow measurement for water, air, steam, oil, and gas in pipes and ducts.

Q4: How accurate is the orifice flow equation?
A: Accuracy depends on proper calibration and installation. Typically ±2-5% with well-designed orifice plates and proper upstream/downstream piping.

Q5: What factors affect discharge coefficient?
A: Orifice geometry, edge sharpness, Reynolds number, and the ratio of orifice to pipe diameter (β ratio) all influence C_d.