1. What is a Flow Rate to Pressure Calculator?

Definition: This calculator determines the pressure difference required to maintain a given flow rate through a pipe using the Hagen-Poiseuille equation.

Purpose: It helps engineers and fluid dynamics professionals analyze pipe systems and predict pressure requirements.

2. How Does the Calculator Work?

The calculator uses the Hagen-Poiseuille equation:

Where:

• \( \Delta P \) — Pressure difference (Pascals)
• \( \mu \) — Dynamic viscosity (Pa·s)
• \( L \) — Length of pipe (meters)
• \( Q \) — Volumetric flow rate (m³/s)
• \( r \) — Pipe radius (meters)

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

3. Importance of Pressure Difference Calculation

Details: Accurate pressure calculations are essential for designing efficient piping systems, selecting appropriate pumps, and ensuring proper fluid flow in various applications.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What viscosity value should I use?
A: For water at 20°C, use 0.001 Pa·s. For other fluids, consult viscosity tables (e.g., honey ~10 Pa·s, air ~0.000018 Pa·s).

Q2: Why is radius to the fourth power?
A: This strong dependence shows that small changes in pipe diameter dramatically affect pressure requirements.

Q3: What are the limitations of this equation?
A: It assumes laminar flow, Newtonian fluids, and smooth, straight pipes of constant diameter.

Q4: How does temperature affect the calculation?
A: Temperature changes viscosity - warmer fluids typically have lower viscosity.

Q5: Can I use this for turbulent flow?
A: No, the Darcy-Weisbach equation would be more appropriate for turbulent flow conditions.