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Chen's formula

Values for calculation

$ N_{Re} $
$ ε $ $ \mathrm{m} $
$ D $ $ \mathrm{m} $
$ L $ $ \mathrm{m} $

Calculation

Friction factor

$$f=\left\{-2\cdot\log_{10}{\left[\cfrac{ε}{3.7065\cdot D}-\cfrac{5.0452}{N_{Re}}\cdot\log_{10}{\left(\cfrac{1}{2.8257}\cdot\left(\cfrac{ε}{D}\right)^{1.1098}+\cfrac{5.8506}{N_{Re}^{0.8981}}\right)}\right]}\right\}^{-2}$$

Loss coefficient

$$ζ=f\cdot\cfrac{L}{D}$$