Pressure Loss

Written by Matt Milbury on . Posted in Pump

presser dropPressure loss, abbreviated as \(\Delta P\), also called pressure drop, is the difference in pressure between two points, usually caused by friction resistance in the pipe, but moisture can also affect it.


Pressure Loss formula

\(\large{ P_l =  \mu  \; \left( \frac{ l_p  }{ d_h } \right) \; \left( \rho\;\frac{ v^2 }{ 2 } \right) }\) 
Symbol English Metric
\(\large{  P_l }\) = pressure loss \(\large{\frac{lbf}{in^2}}\) \(\large{Pa}\)
\(\large{ \rho }\)   (Greek symbol rho) = density \(\large{\frac{lbm}{ft^3}}\) \(\large{\frac{kg}{m^3}}\)
\(\large{ \mu }\)  (Greek symbol mu) = friction coefficient \(\large{ dimensionless }\)
\(\large{ d_h }\) = hydraulic diameter \(\large{ ft }\) \(\large{ m }\)
\(\large{ l }\) = lenght of pipe \(\large{ ft }\) \(\large{ m }\)
\(\large{ v }\) = velocity of fluid  \(\large{\frac{ft}{sec}}\) \(\large{\frac{m}{s}}\)


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Tags: Pressure Equations