# Pressure Differential

Written by Jerry Ratzlaff on . Posted in Thermodynamics

Pressure differential, abbreviated as $$\Delta p$$ or $$p_d$$, is the pressure difference between two points of a system.

## PRESSURE DIFFERENTIAL formulas

 $$\large{ \Delta p = \frac { 1.59923 \; p \; d^4 \; \rho } { m_f^2 } }$$ $$\large{ \Delta p = Eu \; \rho \; U^2 }$$ (Euler number) $$\large{ \Delta p = SG \; \left( {\frac{Q} {C_c} } \right) ^{\frac{1}{2} } }$$ (flow coefficient)

### Where:

$$\large{ \Delta p }$$ = pressure differential

$$\large{ U }$$ = characteristic velocity

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

$$\large{ Eu }$$ = Euler number

$$\large{ C_v }$$ = flow coefficient

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

$$\large{ d }$$ = inside diameter of pipe

$$\large{ m_f }$$ = mass flow rate

$$\large{ p }$$ = pressure change

$$\large{ SG }$$ = specific gravity of fluid (water at 60°F = 1.0000)

$$\large{ C_v = 1.157 \; K_v }$$     (US units)

$$\large{ K_v = 0.8646 \; C_v }$$     (SI )units