Minor losses in pipe flow


Minor losses in pipe flow are a major part in calculating the flow, pressure, or energy reduction in piping systems. Liquid moving through pipes carries momentum and energy due to the forces acting upon it such as pressure and gravity. Just as certain aspects of the system can increase the fluids energy, there are components of the system that act against the fluid and reduce its energy, velocity, or momentum. Friction and minor losses in pipes are major contributing factors.

Minor Losses

Below is a list of common piping components and their kinetic energy factor,.
The kinetic energy factor is used to calculate the configurational head loss, the energy loss to the components of the system. The configurational head loss,, can be calculated using the following equation.
Where:
= Configurational head loss
= Downstream velocity
= Gravity of Earth
= Sum of all kinetic energy factors in system

Friction Losses

Before being able to use the minor head losses in an equation, the losses in the system due to friction must also be calculated.
Equation for friction losses:
= Frictional head loss
= Downstream velocity
= Gravity of Earth
= Hydraulic radius
=Total length of piping
= Fanning friction factor

Total Head Loss

After both minor losses and friction losses have been calculated, these values can be summed to find the total head loss.
Equation for total head loss,, can be simplified and rewritten as:
= Frictional head loss
= Downstream velocity
= Gravity of Earth
= Hydraulic radius
=Total length of piping
= Fanning friction factor
= Sum of all kinetic energy factors in system
Once calculated, the total head loss can be used to solve the Bernoulli Equation and find unknown values of the system.