1. What is a Flow and Pressure 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 technicians calculate fluid flow in pipes for various applications like plumbing, HVAC, and industrial processes.

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 ensure proper system design, energy efficiency, and meet operational requirements in fluid systems.

4. Using the Calculator

Tips: Enter 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 fluids is this calculator suitable for?
A: It works best for laminar flow of Newtonian fluids in circular pipes (Re < 2100).

Q2: What's a typical viscosity value for water?
A: Water at 20°C has viscosity of about 0.001 Pa·s. Higher temperatures decrease viscosity.

Q3: How does pipe radius affect flow rate?
A: Flow rate is proportional to the fourth power of radius - doubling radius increases flow 16 times!

Q4: What units should I use?
A: Use consistent SI units: meters for dimensions, Pascals for pressure, and Pa·s for viscosity.

Q5: Does this work for turbulent flow?
A: No, for turbulent flow you would need to use the Darcy-Weisbach equation instead.