1. What is a Water Flow Rate Calculator PSI?

Definition: This calculator estimates the volumetric flow rate of water through a pipe using the Hagen-Poiseuille equation, with pressure input in PSI.

Purpose: It helps engineers, plumbers, and fluid system designers determine flow rates in laminar flow conditions.

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 (converted from PSI to 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 estimation ensures proper system design, adequate water supply, and efficient energy use in fluid systems.

4. Using the Calculator

Tips: Enter pipe radius in meters, pressure difference in PSI, fluid viscosity (default 0.001 Pa·s for water), 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 (smooth) flow conditions (Re < 2000).

Q2: Why is radius to the fourth power so important?
A: Small changes in pipe diameter dramatically affect flow rate - doubling the radius increases flow 16-fold.

Q3: What's the viscosity of water at 20°C?
A: Approximately 0.001 Pa·s, which is the default value in the calculator.

Q4: How do I convert the result to other units?
A: 1 m³/s = 1000 L/s = 15850.3 gpm (gallons per minute).

Q5: What if my flow is turbulent?
A: For turbulent flow (Re > 4000), you would need to use the Darcy-Weisbach equation instead.