Dry-Lab 1: Friction loss measurement in pipe

Introduction
In this experiment, Fluid Friction Apparatus is used to study the head losses in straight pipes
and pipe fittings with the incompressible fluid due to the friction whereby the pipe fitting includes
tees, elbows and bend. This is to calculate the total pressure of the water required to transfer the
fluid in the pipes from one point to another. Reynold’s Number is calculated is used to determine
whether the fluid flow is either laminar or turbulent. (Roshko 1961) Head loss in pipes is considered
due to the various environment and scenario in real life. Basically, the increase of friction in the
pipes due to viscosity of the liquid will increase the head loss especially at the fittings and this can
lead to the decreasing of the flow rate.

Objectives

This experiment is done in two set whereby the first one is to examine the head loss due to the
friction and the second one is to investigate the head loss due to the various types of pipe fittings.
The first experiment data is collected to compare between laminar and turbulence flow. The second
experiment data is collected to compare with the theoretical calculation of the head loss using pipe
friction equation and make a comparison between the results in smooth bore and roughened pipe.
Meanwhile, the third experiment data is accumulated to determine the head loss due to the various
types of pipe fittings at a constant flow rate and the pipe fittings includes 45o elbow, 45o Y junction,
90o bend and 90o T-junction.
Two experimental rigs were used in this experiment: The Lotus Scientific Rig, which was used to
observe turbulent flow and the Armfield Experimental Rig, which was used to examine laminar
flow.

Figure 1.The Armfield Experimental Rig Figure 2.The Lotus Scientific Rig

Experiment 1
For the Armfield Experimental Rig, the control valve was first closed and the initial value of the
water manometer reading was recorded. The control valve was then opened, allowing water to
flow, and the difference in height between the two manometers were controlled using the valve
and recorded. The volume of water collected from the rig in 60 seconds as well as its temperature
was measured using a measuring cylinder and thermometer respectively, and recorded. Finally,
this process was repeated while varying the difference between the manometer readings in each
trial until 10 sets of data were obtained.
Experiment 2
For the Lotus Scientific Rig, the control valve was adjusted until a reference point was obtained
on the manometer scales. Upon completion of the initial setup, the control valve was turned and
the difference between the heights of the manometer readings were manipulated and noted down.
The exit outlet of the water collection tank was plugged in, while simultaneously a stop watch was
started, in order to record the time taken for 10 liters of water to collect in the tank. The temperature
of this collected water was also recorded. This process was repeated while varying the difference
in heights of the manometer readings in each trial until 8 sets of readings were recorded.

Experiment 3: Head loss due to friction

In experiment 1, the head loss between the length of 1meter smooth pipe was examined and the
result is then compared to the theoretical value calculated. With the reference of Figure in
appendix, the water was pumped into pipe (4) and the valves which was connecting the pipe was
allowed to be open to keep the water flowing through the pipe. Before the system is pumped with
water, manometer probes were connected to the tapping of the pipe that is concerned and the
water was transmitted throughout the whole pipe system to eliminate the bubbles trapped inside
the system. A stopwatch was used to record the time taken to fill up a 10-litre amount of water in
a side tube with the specific flow rate. The time taken was recorded twice to obtain a more precise
and accurate result. Meanwhile, the head loss is determined by observing the upper and lower
meniscus of the manometer. The experiment is repeated with 5 different water flow rates by
adjusting the valve.

Experiment 4: Head loss due to pipe fittings

In experiment 2, the head loss between the tappings for the for various type of fitting were
examined and the result is compared to the theoretical value calculated. With the reference of
Figure in appendix, there are 4 pipe fittings are used whereby they are 45° elbow (8), 45° Y-
junction (9), 90° bend (14) and 90° T-junction (15) respectively. The pressurized manometer
probes were then connected to the tapping of the 45° elbow fitting. A stopwatch was used to
record the time taken to fill up a 10-litre amount of water in a side tube with the specific flow
rate and it was repeated twice to obtain an accurate and precise result. The reading of the upper
and lower meniscus of manometer was noted in order to determine the head loss. The experiment
is then continued using the same steps by shifting the pipe fitting to 45° Y-junction (9), 90° bend
(14) and 90° T-junction (15).
 Data Collection
Experiment 1
Density of mercury = 13600kg/m3, and density of air = 1.23 kg/m3
Table 1. Table of results for Laminar Flow.
Laminar Flow (Armfield Experimental Rig)
Pipe Length = 500mm, Pipe Diameter 3mm

No Flow Rate Water Water Manometer Density Dynamic

Volume Time Temperature h1 h2 ∆𝐡 (kg/m3) Viscosity
(mL) (s) (C) (mm) (mm) (mm) (kg/m s)
1 60 60.25 29 255 275
2 138 60.25 30 238 285
3 185 60.31 30 230 295
4 225 60.13 30 210 305
5 263 60.13 30.5 195 315
6 285 60.25 31 185 325
7 290 60.13 31 175 335
8 305 60.31 31 162 345
9 340 60.13 31 135 365
10 380 60.25 31 105 385

Experiment 2
Table 2.Table of results for Turbulent Flow.
Turbulent Flow (Lotus Scientific Rig)
Pipe Length = 320mm, D = 7.7mm

No Pipe Flow Rate Water Mercury Manometer Density Dynamic

Diameter Volume Time Temperature h1 h2 ∆𝐡 (kg/m3) Viscosity
(mm) (L) (s) (C) (mm) (mm) (mm) (kg/m s)
1 7.7 10 43 28 245 360
2 7.7 10 40.60 28 235 370
3 7.7 10 39.13 28 225 380
4 7.7 10 47.02 28 255 350
5 7.7 10 51.59 28 265 340
6 7.7 10 61.00 28 275 330
7 7.7 10 85.00 28 285 320
8 7.7 10 133.00 28 295 310

Result Experiment 1: Laminar flow

No Q ( m3/s) Velocity (m/s) Reynold number ∆𝑷 (Pa) f Head loss
 For Tubulent flow
No Q ( m3/s) Velocity (m/s) Reynold number ∆𝑷 (Pa) f Head loss

Plot diagram of Re vs f
Plot diagram head loss vs velocity

Experiment 3

Table 3: Water Manometer Readings

Test Qty Δt (s) Flow u h1 h1 Measured

No. (1) Δt2 Δtavg rate Q (m/s) (mm) (mm) head loss, hL
Δt2 (m3/s) (m H2O)
1 10 41 42 0.000241 840 763

2 10 25 25 0.000400 870 690

3 10 20 21 0.000488 900 635

4 10 17.5 17.5 0.000571 925 655

5 10 16 16 0.000625 950 500

Table 4: Results Sheet

Test Measured head u (m/s) Reynolds number, Friction coefficient, f Calculated head
No. loss, hL (m H2O) Re (from Moody chart) loss, hL (m)

5
 Experiment 4

Table 5: Water manometer readings

Test Qty Δt (s) Flow u 45° Elbow 45° Y 90° Bend 90° T
No (l) rate Q (m/s) Junction Junction
(m3/s)
Δt2 Δtavg h1 h2 h1 h2 h1 h2 h1 h2
Δt2
(m) (m) (m) (m) (m) (m) (m) (m)

1 10 41 42 0.000241 801 787 815 778 820 773 800 794

2 10 25 25 0.000400 810 735 800 740 825 710 780 755

3 10 20 21 0.000488 810 695 795 910 835 660 760 740

4 10 17.5 17.5 0.000571 800 645 755 660 825 595 725 695

5 10 16 16 0.000625 785 605 755 620 820 535 690 660

Table 6: Fitting factor

Fitting factor, KL (Calculated) Fitting factor, KL (Theoretical)

Test 45° 45° Y 90° 90° T 45° 45° Y 90° Bend 90° T
Elbow Junction Bend Junction Elbow Junction Junction
No.

4
5

Table 5: Deviation of fitting factor

Deviation (%)
Test No 45° Elbow 45° Y Junction 90° Bend 90° T Junction

1
2
3
4
5
Table 6: Head loss in each pipe fittings

Measured head loss, hl (m) Theoretical head loss, hl (m)

Test 45° 45° Y 90° 90° T 45° 45° Y 90° 90° T
Elbow Junction Bend Junction Elbow Junction Bend
No. Junction

1
2
3
4
5