Introduction of Flow Through Pipes

• Pipes are closed conduits used to carry fluids under pressure. 

• Circular cross section pipes are used commonly. 

• Pipes carrying fluids under pressure are always running full. 

• The fluids flowing in a close conduit are always subjected to resistance due to boundary shear between fluid particles and the pipe walls and also between the fluid particles due to fluid viscosity.

• This is termed as frictional resistance, which is the resistance to the fluid flow. 

• There will always be some loss of energy in the direction of flow as a certain amount of energy possessed by the flowing fluid will be consumed in overcoming this resistance to the flow.

• This loss of energy however depends on flow type.

• The flow of fluid in a pipe can either be laminar or turbulent. 

• We need to have separate laws to deal with laminar and turbulent types of flow in pipes as fundamentally these are governed by different laws.

Minor Losses

The minor loss of energy includes the following cases :

1. Sudden enlargement.

2. Sudden contraction.

3. An obstruction in the pipe.

4. At the entrance to a pipe.

5. At the exit of a pipe.

6. Bend in the pipe.

7. Various pipe fittings.