1. What is Flow Rate from 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 scientists calculate laminar flow in pipes based on pressure difference and fluid properties.

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, medical devices (like IV drips), and industrial fluid transport systems.

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 types of flow does this equation apply to?
A: The Hagen-Poiseuille equation applies only to laminar (not turbulent) flow in long, straight pipes of constant circular cross-section.

Q2: What's a typical viscosity value for water?
A: Water at 20°C has a viscosity of about 0.001 Pa·s. The calculator uses this as the default value.

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

Q4: What are the limitations of this equation?
A: It assumes steady, incompressible, laminar flow of a Newtonian fluid in a straight pipe with no-slip boundary conditions.

Q5: How can I check if flow is laminar?
A: Calculate the Reynolds number (Re). Flow is typically laminar when Re < 2100.