pipefriction
TRANSCRIPT
-
8/7/2019 PipeFriction
1/3
Hydraulics & Hydraulic Machines Lab Lab Manual
DETERMINATION OF FRICTION FACTOR OF PIPE
LINES
Aim:-
To determine Darcy Friction Co-efficient and to study the flow of liquids in pipes
Apparatus:-
1. Pipe line of four different diameters of G.I & P.V.C (Experimental set up).
2. Stop clock.
Theory:-
A closed conduit of any cross section used for flow of liquid is known as a pipe. When
water flows through a pipe, a certain amount of energy (or pressure energy) has to be spent to
over come the friction due to roughness of the pipe surface. This roughness or frictional effect
depends upon the material of the pipe and scale formation, if any. When the surface is smooth,
the friction effect is less. The frictional losses also vary with the velocity of flow or depending
upon the flow conditions that is laminar, transition or turbulent. The resistance is of two types
depending upon the velocity of flow.
1. Viscous resistance and
2. Frictional resistance, due to different diameters.
Description:-
The test rig consists of a piping circuit of four different diameters made of G.I & P.V.C.
The pipes are parallel. Using the gate valves provided in each pipeline, water is made to flow in
one pipeline at a time. There is a U-Tube manometer within a stabilizing valve to measure the
pressure difference across the tapings, one at either end of the pipeline fitted with a Ball valve.
The equipment also consists of a constant steady supply of water with a means of varying the
flow rate using Centrifugal pump. A measuring tank is provided to measure the flow rate.
Rotameter is used for the direct measurement of water flow rate through pipes.
Formulae:-
Darcys formula for finding the loss of head in a pipe is,
gd
vfh
2
142
=
Where, h = the loss of head due to friction =12.6*H
AL HABEEB COLLEGE OF ENGINEERING & TECHNOLOGY 1
-
8/7/2019 PipeFriction
2/3
Hydraulics & Hydraulic Machines Lab Lab Manual
l=the length of the pipe
f= frictional factor or Co-efficient.
H = Differential head in mm of Hg
f = 2 h d g
4 l V2
V = Q m/sec where Q = A R m3/sec
a 100x t
R is raise in water in cm
t is time in seconds
. a = cross sectional area of pipe in m2
Data:-
Area of measuring tank, A = 0.125 sq. m.
Length of pipe , l = 1.5 m.
Density of water, = 1000 Kg/cu.m
Acceleration due to gravity, g = 9.81 m/sec2
Diameter of pipe, d = 27, 9, 12.5mm (G.I), 25mm (P.V.C)
Procedure:-
1) Select the required Pipeline.2) Open the appropriate pressures cocks and close all other pressure cocks (ball valves).
3) Adjust the flow through the control valve of the pump
4) Vent the manometer to remove the air bubbles.5) Note down the differential head reading in the manometer.
6) Collect the water in the collecting tank and close the butterfly valve to note down the
collecting tank reading against the known time.
7) Change the flow rate and repeat the experiment for different diameters of the pipe.
AL HABEEB COLLEGE OF ENGINEERING & TECHNOLOGY 2
-
8/7/2019 PipeFriction
3/3
Hydraulics & Hydraulic Machines Lab Lab Manual
Tabular Form:-
Dia/type
of pipemm
Manometer reading Head loss
HMeters
Time for
10 cm riset sec
Flow rate
QCu.m/sec
Darcys
Constantf
H1
Meters
H2
Meters
1.
2.
3.4.
1.2.
3.
4.
1.
2.
3.4.
1.2.
3.
4.
Precautions:-
1. Do not start the pump if voltage is less than 180V.
2. Vent the manometer.
3. Frequently grease the rotating parts.
Result:-
AL HABEEB COLLEGE OF ENGINEERING & TECHNOLOGY 3