PLAIN AND CIVIL: EXAMPLE 6.2.2 FRICTION FACTOR USING THE MOODY DIAGRAM

Thursday 18 April 2019

EXAMPLE 6.2.2 FRICTION FACTOR USING THE MOODY DIAGRAM

Determine the friction factor of a 20-mm diameter new cast iron pipe with fluid of $\upsilon =1.4x10^{-4}\frac{m^{2}}{s}$ with a velocity of $24.62\frac{m}{s}$ .

The two parameters needed in using the Moody diagram are the Reynold's number and the relative roughness. The Reynold's number should show a turbulent flow.

$R_{e}=\frac{vD}{\upsilon }=\frac{0.62*0.020}{1.4x10^{-4}}=3517.14>2100$

For relative roughness (k for new cast iron pipe = 0.00085)

$\frac{k}{D}=\frac{0.00085}{0.020}=0.0425$

Thus, from the Moody diagram, f= 0.077.