1. What is a Pipe Pressure Flow Rate Calculator?

Definition: This calculator determines the volumetric flow rate of a fluid through a pipe using the Hagen-Poiseuille equation.

Purpose: It helps engineers and fluid dynamics specialists analyze laminar flow conditions in pipes.

2. How Does the Calculator Work?

The calculator uses the Hagen-Poiseuille equation:

Where:

• \( Q \) — Volumetric flow rate (m³/s)
• \( r \) — Pipe radius (m)
• \( \Delta P \) — Pressure difference (Pa)
• \( \mu \) — Dynamic viscosity (Pa·s)
• \( L \) — Pipe length (m)

Explanation: The flow rate is directly proportional to the pressure difference and the fourth power of the radius, and inversely proportional to viscosity and pipe length.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculations are essential for designing piping systems, predicting fluid behavior, and ensuring efficient system operation.

4. Using the Calculator

Tips: Enter the pipe radius (in meters), pressure difference (in Pascals), fluid viscosity (default 0.001 Pa·s for water at 20°C), and pipe length (in meters). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What flow regime does this equation apply to?
A: The Hagen-Poiseuille equation applies only to laminar (not turbulent) flow in long, straight pipes.

Q2: Why is radius to the fourth power?
A: The r⁴ relationship shows how dramatically pipe diameter affects flow rate - doubling the radius increases flow 16 times!

Q3: What's a typical viscosity value for water?
A: Water at 20°C has viscosity of about 0.001 Pa·s, which is the default value in the calculator.

Q4: Can I use this for gases?
A: Only for gases in laminar flow conditions. Most gas flows are turbulent, requiring different equations.

Q5: How do I convert to other units?
A: 1 m³/s = 1000 L/s = 15850 gpm (US gallons per minute). Pressure conversions: 1 Pa = 0.000145 psi.