Friction Factor

Item Data
Formula Calculation Friction Factor
Drawing
Nomenclature f/2=friction factor
D=Pipe diameter in m
um=mean velocity in m/s
ΔPf=pressure drop due to friction in Pa
L=length of pipe in m
ρ=specific gravity in kg/m3
Usual Values In Laminar regime f/2=8/Re
In turbulent regime, different correlations can be used
Blasius (only applicable to smooth pipes f/2=0.023.Re-0.20
Churchill (applicable for any Re and ratio e/D)
Calculation of Churchill Correlation
With e the pipe roughness in m
Another possibility is to use the Moody Diagram
Related In Laminar regime, the volumic flowrate can be calculated thanks to the Hagen-Poiseuille equation
Hagen Poiseuille Law
Q=volumic flowrate in m3/s
μ=dynamic viscosity in Pa.s
Source Mecanique et Rheologie des fluides en genie chimique, Midoux, Lavoisier 1993, page 162, page 274-275