Darcy-Weisbach Equation

Written by Jerry Ratzlaff on . Posted in Dimensionless Numbers

Darcy-Weisbach Equation ( \(DW\) ) (dimensionless number) is the most common way of expressing the pressure drop of a piped fluid is to use the.  The equation is valid for fully developed, steady state and incompressible flow. The Darcy-Weisbach equation with the Moody Diagram are considered to be the most accurate model for estimating frictional head loss in steady pipe flow.

Darcy-Weisbach Equation FORMULA

\(\large{ h_l = \frac   { f   l   v^2   }   { D  g   }   }\)         

Where:

\(\large{ h_f }\) = head loss due to friction

\(\large{ f }\) = friction factor

\(\large{ g }\) = gravitational acceleration

\(\large{ D }\) = inside diameter

\(\large{ l }\) = length

\(\large{ v }\) = velocity of the fluid

Solve for:

\(\large{ f = \frac   { 2  {h_f}    D  g }   { l   {v^2}   }   }\)

\(\large{ l = \frac   { 2  {h_f}    D     g  }   { f  v^2   }   }\)

\(\large{ D = \frac   { f   l   v^2   }   { 2   {h_f}   g  }   }\)

\(\large{ v =   \sqrt {  \frac  { 2  {h_f}   D    g   }   { fl   }        }   }\)

\(\large{ g = \frac   { f  l    v^2   }   { 2  {h_f}  D  }   }\)

 

Tags: Equations for Flow Equations for Pipe