Introduction
The main purpose of this lab experiment is to investigate on the head loss
caused by pipe friction associated with the flow of water through the different
sizes and roughness of pipes and compare the experimental results to
theory.
Objectives
At the end of the laboratory activities, students would be able to:
Identify the type of flow when the water flows in various sizes and
roughness of pipes and at different flow rates.
Identify how the flow velocity affects the pressure loss
Measure the friction factor, for laminar and turbulent flow.
Plot a graph which shows the relationship between head loss and
discharge
Theoretical and Background:
It was first demonstrated by Reynolds that two types of flows may exist in a
pipe:
1. Laminar flow at low velocities
2. Turbulent flow at higher velocities
These two types of flows are separated by a transition phase where no
definite relationship between h and u exists.
For a circular pipe with fully developed flow, the head loss due to friction may
be calculated from the formula:
Where: L is the length of pipe between the tapping; d is the internal
diameter of the pipe ; u is the mean velocity of water through the pipe (in
m/s) ; g is acceleration due to gravity (m/s2); λ is the pipe friction coefficient.
Reynolds number can be found using:
After determining the Reynolds number for the flow in the pipe, the value of λ
may be determined using Moody diagram
Fig 1 Moody diagram
Laboratory Equipment
The fluid flow system in our lab consists of a tank, a pump, and five lines in
parallel. A figure of the equipment with several key elements is provided
below.
Fig 2 losses in pipe system equipment
PROCEDURE
Procedure
Preparation of the Experimental Setup:
Begin by ensuring that the experimental setup is correctly
assembled and all components are securely connected. This
initial step is crucial for obtaining accurate measurements and
results.
Removal of Air Bubbles:
Carefully remove any air bubbles present in the linings of the
tubes connecting the manometer to the pipes. Air bubbles can
significantly affect the accuracy of the measurements by
introducing errors in the pressure readings.
Connection of Manometers:
Connect the manometers to the long pipe. Ensure that the
connections are tight and leak-free to prevent any loss of
pressure or fluid during the experiment.
Setting the Flow Rate:
Adjust the flow rate in the rotameter to the desired values. The
flow rate is a critical parameter in the study of head loss and
must be set according to the experiment's requirements.
Observation of Manometer Readings:
Once the flow rate is set, observe and record the change in the
height of the fluid in the manometers. These readings are
essential for calculating the head loss in the pipes.
Note . If any result is suspect, repeat the measurement .
Observations, Calculations and Results:
Complete the table below and then plot a graph of h vs. u for each size of
pipe. Identify the laminar, transition and turbulent zones on the graphs
Volu Tim Flo Pip Velocit Reynold` From Head Head loss
me e w e yu s number Moody loss Measured h
V T rate dia diagram Calculat (meters of
Q ʎ ed water)
Note . Each student is required to submit a technical report of the
laboratory result highlighting the apparatus used, the procedure undertaken
for the test data acquisition process, analysis carry out, and the relevancy of
these tout output to address the given problem. Discussion of the report
should also contain the discrepancies between experimental and theoretical
results
