Air Flow Rate Calculator Pressure And Diameter

Bernoulli Equation for Orifice/Pipe:

\[ Q = \pi (D/2)^2 \sqrt{\frac{2 \Delta P}{\rho}} \]

Flow Rate (Q):

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1. What Is The Bernoulli Equation For Orifice/Pipe?

The Bernoulli equation for orifice/pipe flow calculates the volumetric flow rate of air or fluid through a pipe or orifice based on pressure differential, diameter, and fluid density. It's derived from the principle of conservation of energy in fluid dynamics.

2. How Does The Calculator Work?

The calculator uses the Bernoulli equation:

\[ Q = \pi (D/2)^2 \sqrt{\frac{2 \Delta P}{\rho}} \]

Where:

\( Q \) — Volumetric flow rate (m³/s)
\( D \) — Diameter of pipe/orifice (m)
\( \Delta P \) — Pressure drop across the orifice (Pa)
\( \rho \) — Density of the fluid (kg/m³)
\( \pi \) — Mathematical constant pi (approximately 3.14159)

Explanation: The equation calculates flow rate by considering the cross-sectional area of the pipe and the velocity derived from pressure difference and fluid density.

3. Importance Of Flow Rate Calculation

Details: Accurate flow rate calculation is essential for HVAC system design, pneumatic system optimization, industrial process control, and ventilation system engineering.

4. Using The Calculator

Tips: Enter diameter in meters, pressure drop in Pascals, and density in kg/m³. All values must be positive numbers. For air at standard conditions, density is approximately 1.225 kg/m³.

5. Frequently Asked Questions (FAQ)

Q1: What Is The Typical Density Value For Air?
A: At standard conditions (20°C, 101.325 kPa), air density is approximately 1.225 kg/m³. Density varies with temperature and pressure.

Q2: How Accurate Is This Equation For Real-World Applications?
A: The equation provides theoretical flow rates. Real-world applications may require discharge coefficients to account for energy losses and flow restrictions.

Q3: Can This Be Used For Liquids As Well As Gases?
A: Yes, the equation works for both liquids and gases, but the density value must be appropriate for the specific fluid being measured.

Q4: What Are Common Pressure Drop Ranges In HVAC Systems?
A: Typical pressure drops range from 50-500 Pa for ventilation systems, depending on duct size, length, and airflow requirements.

Q5: How Does Temperature Affect The Calculation?
A: Temperature affects fluid density. Higher temperatures decrease density, which increases flow rate for the same pressure drop.