Introduction:
Pipes are widely used
in engineering to deliver fluid from one place to another. There are two types
of flow.
Laminar flow (smooth
flow) :
Flow
in discrete layers with no mixing (Re<2000)
Turbulent flow:
Flow
with eddy or mixing action (Re>2000)
Transition region:
2000<Re<4000
(Reynolds Number is used
to predict the laminar/turbulent flows)
µ=viscosity
Normally, flow sections
of circular cross section are mentioned to as pipes (when the fluid is a
liquid), and flow sections of non circular cross section as ducts (when the
fluid is a gas).
To pass the liquid used
circular cross section pipes, because that can withstand large pressure heads
between inside and outside.
Let us consider the
velocity profile in a pipe flow.
The fluid velocity of
pipe surface is zero, because of no friction. The maximum velocity acting at
the center of the pipe. When practically, if the pipe diameter is content, used
average velocity.
Head loss in a pipe
flow
First, derive a general
equation for head loss in a pipe.
The total energy of a
fluid (Total Head) = kinetic energy + potential energy + pressure
=
P + 1/2
v2
+ Z
( unit is Pa )
v2
+ Z ( unit is Pa )
If there is no energy
loss,
Total Head @ 1 = Total Head @2
If there is a head gain
in a pipe,
If there is a head gain
in a pipe,
** liquids flow from a
point of high head to low head.
If the pipe diameter is
constant, there have formula to can be directly applied.
This formula called Darcy-Weisbach
equation.
hf is energy loss
L is the pipe length
v is the mean
