1. What is a Pipe Flow Calculator?

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

Purpose: It helps engineers and technicians determine fluid flow rates in laminar flow conditions for pipe system design and analysis.

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 equation describes laminar flow of an incompressible, Newtonian fluid in a long, straight pipe of constant circular cross-section.

3. Importance of Pipe Flow Calculation

Details: Accurate flow rate calculations are essential for designing piping systems, predicting pump requirements, and ensuring proper system operation.

4. Using the Calculator

Tips: Enter pipe radius (default in meters), pressure difference, viscosity (default 0.001002 Pa·s for water at 20°C), and pipe length. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What types of flow does this equation apply to?
A: The Hagen-Poiseuille equation applies only to laminar flow (Re < 2100) in straight, circular pipes.

Q2: What's a typical viscosity value for water?
A: Water at 20°C has a viscosity of about 0.001002 Pa·s (1.002 cP).

Q3: Why is radius to the fourth power so important?
A: The strong dependence on radius means small changes in pipe diameter dramatically affect flow rate.

Q4: Can I use this for turbulent flow?
A: No, for turbulent flow you would need to use the Darcy-Weisbach equation instead.

Q5: What units should I use?
A: Use consistent SI units: meters for dimensions, Pascals for pressure, and Pa·s for viscosity.