# Pressure Drop

Written by Matt Milbury on . Posted in Pump

## Pressure Drop

The difference in pressure between two points, usually caused by friction resistance in the pipe, but moisture can also affect it.

### Pressure Drop Formula

A relationship for turbulent flow in commercial steel pipes is:

$$\large{ \Delta P = \frac{Q^{1.8} \mu^{0.2}}{C \cdot d^{4.8} \cdot \rho} }$$

Where:

$$\large{ \Delta P }$$ = pressure loss due to friction

$$\large{ \mathrm {C} }$$ = 20,000 for rough carbon steel pipe and 23,000 for smooth tubes.

$$\large{ d }$$ = the internal pipe diameter

$$\large{ \rho }$$   (Greek symbol rho) = density of the fluid

$$\large{ Q }$$ = flow rate

$$\large{ \mu }$$   (Greek symbol mu) = viscosity