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Churchill correlation (friction factor)

1. Introduction
2. Churchill equation

1. Introduction

The friction factor is used to calculate the pressure drop due to the flow of a fluid in a pipe. It represents the interaction in between the fluid and the pipe. There are different ways to calculate it, one can be graphical, using a Moody graph, but for automating calculation it is not practical, thus correlations are required. The Colebrook correlation is usually admitted as being accurate enough for most industrial applications but presents a difficulty as it does not explicitly express the friction factor, that is why it may be interesting to consider Churchill equation that allows to directly calculate the friction factor.

Note that the friction factor used here is Darcy (also called Darcy-Wesibach or Moody) friction factor.

2. Churchill equation

Churchill equation

With :
f = Darcy friction factor
D = Pipe diameter (m)
Re = Reynolds number
ε = pipe roughness (m)


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