Hagen–Poiseuille Equation

Hagen–Poiseuille equation, also called Hagen–Poiseuille Law, Poiseuille equation, or Poiseuille law, gives the pressure loss in a fluid flowing through a long cylindrical pipe.

 

Hagen–Poiseuille Equation formula
\(\large{ \Delta p = \frac { 8 \; \mu \; l \; Q }{ \pi \; r^4 }   }\)
Symbol	English	Metric
\(\large{ \Delta p }\) = pressure loss	\(\large{\frac{lbf}{in^2}}\)	\(\large{Pa}\)
\(\large{ \mu }\)  (Greek symbol mu) = dynamic viscosity	\(\large{\frac{lbf-sec}{ft^2}}\)	\(\large{Pa-s}\)
\(\large{ l }\) = length of pipe	\(\large{ft}\)	\(\large{m}\)
\(\large{ \pi }\) = Pi	\(\large{3.141 592 653 ...}\)
\(\large{ r }\) = pipe inside diameter	\(\large{in}\)	\(\large{mm}\)
\(\large{ Q }\) = volumetric flow rate	\(\large{\frac{ft^3}{sec}}\)	\(\large{\frac{m^3}{s}}\)