Pressure Drop Calculator
Calculate total pressure drop along a pipe from friction losses using fluid properties.
Queda de Pressão
39.1 kPa
Pressure Drop vs Friction Factor (f)
Formula
## Pressure Drop in Pipes Pressure drop is the energy lost to friction as fluid flows through a pipe. ### Formula **delta_P = f (L/D) (0.5 rho V^2)** This is the Darcy-Weisbach equation expressed in pressure units (Pa) rather than head (m). The two forms are related by delta_P = rho g h_f.
Exemplo Resolvido
Water at 2.5 m/s through 80 mm pipe, 50 m long, f = 0.02.
- 01D = 0.08 m, L/D = 50/0.08 = 625
- 02Dynamic pressure = 0.5 x 1000 x 2.5^2 = 3125 Pa
- 03delta_P = 0.02 x 625 x 3125 = 39,063 Pa = 39.1 kPa
- 04Head loss = 39,063 / (1000 x 9.81) = 3.98 m
Perguntas Frequentes
What causes the highest pressure drop?
Small diameter pipes cause the highest pressure drop because velocity increases as D^-2 and the L/D ratio increases. Doubling the pipe diameter reduces pressure drop by roughly a factor of 32 for the same flow rate.
How do I reduce pressure drop in a system?
Increase pipe diameter, reduce pipe length and number of fittings, smooth the interior surface, or reduce flow rate. Using schedule 40 instead of schedule 80 pipe also slightly increases the bore diameter.
What pressure drop is acceptable?
This depends on the system. For water distribution, 1-3 kPa per metre of pipe is common. For HVAC ducting, 0.8-1.5 Pa/m is typical. Excessive drop requires larger pumps or fans and wastes energy.
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