Darcy-Weisbach Pressure Drop Calculator
Calculate pipe pressure drop using the Darcy-Weisbach equation from friction factor, pipe geometry, fluid density, and flow velocity.
How to Use the Darcy-Weisbach Calculator
- Determine the Darcy friction factor (f = 64/Re for laminar; use Moody chart for turbulent).
- Enter pipe length, inner diameter, fluid density, and mean flow velocity.
- Click Calculate to get pressure drop in Pa and kPa.
Use Cases
- •Pipe sizing for water supply and process piping systems.
- •Pump selection based on system pressure losses.
- •HVAC duct and chilled water system design.
Formula
ΔP = f × (L/D) × (ρv²/2), where f is the Darcy friction factor, L is pipe length (m), D is diameter (m), ρ is density (kg/m³), v is velocity (m/s).
Frequently Asked Questions
How do I find the Darcy friction factor?
For laminar flow (Re < 2300): f = 64/Re. For turbulent flow, use the Moody chart or Colebrook equation. Typical values range from 0.01 to 0.05 for smooth pipes.
What is the difference between Darcy and Fanning friction factor?
The Darcy friction factor is 4 times the Fanning factor. This calculator uses the Darcy (Moody) friction factor, which is more common in pipe flow calculations.
Is this calculator free?
Yes, all OhMyCalc calculators are completely free to use.