Friction in Pipe

 

Energy Head Loss,Hl

Major Head Loss,Hf

• ​Friction occur along the pipe.

Minor Head Loss,hm

• Friction occur when there is a flow disruption along the pipe (entrance).

 

 

 

 

 

 

 

 

 

 

 

Factors that affect head loss

A)  Flow rate

B)  Diameter of the pipe

C)  Roughness of the pipe wall

D)  Corrosion and scale deposits

E)  Viscosity of liquid

F)   Length of pipe

G)  Fittings

H)  Straightness of pipe

 

 

Friction in Circular Conduits

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Friction in non-circular Conduits

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Hagen-Poiseuille equation for Laminar flow

 

 

 

 

 

 

 

 

 

 

Friction factor,f

The loss of head resulting from the flow of a fluid through a pipeline is expressed by the Darcy Formula

 

 

 

 

 

 

 

 

 

Friction factor in laminar flow

 

 

 

 

 

indicating that the friction factor is proportional to viscosity and inversely proportional to the velocity, pipe diameter, and fluid density under laminar flow conditions. The friction factor is independent of pipe roughness in laminar flow because the disturbances caused by surface roughness are quickly damped by viscosity.

 

 

 

Friction factor in turbulent flow

In turbulent flow, relative roughness contributes a significant part besides Reynolds Number. Friction factor can be calculated by using the table below: