EXPERIMENT
PIPE
FRICTION
1. Objective
Study of losses due to
friction in pipes- Determine losses due to friction and the friction factor for
Darcy-Weisbach equation.
2.
Introduction
Pipe flow under pressure
is used for a lot of purposes. A fundamental understanding of fluid flow is
essential to almost every industry related with chemical engineering. In the
chemical and manufacturing industries, large flow networks are necessary to
achieve continuous transport of products and raw materials from different
processing units. This requires a detailed understanding of fluid flow in
pipes. In this experiment you will investigate the frictional forces inherent
in laminar and turbulent pipe flow. By measuring the pressure drop and flow
rate through a pipe, an estimate of the coefficient of friction (friction
factor) will be obtained. In 1883, Osborne Reynolds performed experiments on
fluid flow to determine the laws of frictional resistance. He found that flows
in pipes of different diameters and different fluids could be related to each
other using the dimensionless parameter (now known as the Reynolds Number).Pipe
can be arranged in series or parallel. In series fluid follows a single path
throughout the system and in parallel, it consist of two junctions such that
head loss is same. Whether the pipes are in series or parallel friction
equation should be satisfied for each pipe. There can be only one value of head
at any point. Algebraic sum of all flow rates at any junction is zero. Pipe
losses in a piping system is results from number of characteristics like pipe
friction, change in direction of flow, change in cross-sectional area. Losses
are of two types – Major (The
friction loss in a uniform, straight sections of pipe) and Minor (Factors other
than straight pipe flow induce friction loss). In major loss friction loss is
influenced by whether the loss is laminar (Re<2000) or turbulent (Re>
3000). Like pipe friction, Major losses
are roughly proportional to the square of the flow rate. Darcy equation can be used to calculate the value of
friction factor in the case of laminar and the turbulent flow. Friction factor friction
factor is a function of pipe roughness in addition to Reynolds number and is
combination of form friction and skin friction.
D =
diameter of the pipe; V = velocity
ρ =
density
of fluid
µ =
viscosity of fluid; F- friction factor
3. Procedure
1) First check apparatus
is working properly or not. Check whether is some leakage or not. Fill the
water in the sump tank. Shut on the main power.
2) Shut down all the
valves except the required one.
3) With the valve partly
open to allow water to flow through the system, any trapped air is removed by
manipulation of the flexible connecting pipes. Particular care should be taken
to clear all air from the piezometer connections. The valve is then closed, the
levels in the two limbs of the manometer should settle to the same value
4) Turn on the pump. Thus
water flow through the lower pipe. For the lower pipe there are three cases
when control valve is fully, half and partially opened.
5) Allow water to flow
for 15 seconds in the measuring tank and note down the height attained in the
measuring tank.
6) Perform the above
steps for different flowrates by adjusting the respective valves.
Repeat the above
procedure for the upper pipe.
4. Precaution
1. There should be no air
bubbles in the pipe.
2. Overheating may cause the motor to stop
working.
3. Have the instructor
adjust the water supply to avoid damage to the apparatus.
5.
Results and Discussions
CASE
1.1
|
MANOMETER READING
|
CALCULATION
OF FLOW RATE (
MEASURING TANK READING) (
THEORITICAL)
|
