Bangladesh University of Engineering and Technology

ME 224 (IPE)
Level -3 Term -1
Fluid Mechanics and Machinery Sessional
Credit Hour: 1.5 Cr. Hr. Contact Hour: 3 Hrs

Name of Experiments:

Exp. 1: (a) Verification of Bernoulli’s Principle.

(b) Study of pipe friction.
Exp. 2: (a) Study of flow meters.
(b) Study of Minor losses.
Exp. 3: Study of flow through a circular pipe.
Exp. 4: (a) Study and performance test of a Pelton wheel.
(b) Identification of various parts of a hermetically sealed compressor.
Exp. 5: (a) Performance test of a centrifugal pump.

(b) Study of centrifugal pumps in series and parallel connections.

Exp. 6: (a) Study and performance test of a submersible pump.

(b) Dismantling and assembling of a centrifugal pump.

Exp. 7: Study and performance test of a positive displacement pump.

Experiment No.1
(a) Verification of Bernoulli’s Principle.
(b) Study of pipe friction.
Experiment Outcomes
The objective of this experiment is to verify Bernoull’s equation and investigate the viscous fluid
flow through a circular pipe flow, study the flow regimes and determine the friction factor. On
completion of the experiment, the students should be able to
1. demonstrate the relationship between pressure head and kinetic head
2. determine the friction factors using the Moody diagram
3. estimate the head loss in a pipe flow

Bernoulli's principle
Bernoulli’s equation for an ideal (inviscid or frictionless) incompressible (density does not change
with applied pressure) fluid, irrotational (zero vorticity) and steady flow (does not change the
flowrate with time) is given by

P V2
+ + Z = Total head ( H ) = Constant
 2g

Where, P = pressure
V = fluid velocity
γ = specific weight of fluid
Z = datum head
If there is a head loss Hf, duet to friction, Bernoulli’s equation in this case becomes

Pi Vi 2 Pj V j2
+ + Zi = + +Zj + Hf
 2g  2g

Where, subscript i, j indicate the quantities at point i and j in the fluid flow field.

P
A piezometer tube records the pressure head at the channel centerline. If the datum head is Z,

P 
the piezometer tube record  + Z  above the datum base line. A curve joining the piezometer
 

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 V2
levels constitutes the hydraulic gradient line. Addition of the total velocity head to the
2g
piezometer readings results in the total energy for the incompressible flow.

In more general flow conditions, the EGL (Energy Gradient Line) will drop slowly due to friction
losses and will drop sharply due to a substantial loss (a valve or obstructions) or due to work
extraction (to a turbine). The EEGL can rise only if there is work addition (as from a pump or
propeller). The HGL (Hydraulic Grade Line) generally follows the behavior of the EGL with
respect to losses or work transfer, and it rises and/or falls if the velocity decreases and/or increases.

Friction Factor
In fluid dynamics, the head is a concept that relates the energy in an incompressible fluid to the
height of an equivalent static column of that fluid. In the case of flow over or through a solid
surface (for example: pipe flow), head loss is obvious. This is due to the viscous action (friction)
between the fluid and solid surfaces. The viscosity of fluid (μ) is responsible for head loss. This
loss is known as major loss. Although the head loss represents a loss of energy, it does not represent
a loss of total energy of the fluid. The total energy of the fluid is conserved. The part of energy

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which is lost is utilized by the flow to overcome the skin friction drag. In a fully developed laminar
pipe flow, the head loss is given by:

32 LV  64  L V 2 L V2
hf = = = f (1)
 gD 2  VD  D 2 g D 2g

where, hf = the head loss (m), f = Darcy friction factor, L = the pipe length (m), D = the hydraulic
diameter of the pipe (m), g = the constant for gravitational acceleration (m/s2) and V = the mean
flow velocity (m/s). In this equation, f is the Darcy-Weishbach friction factor (or commonly
known as “friction factor”) which is given by:

64 64
f = =
VD Re

where, Re is the Reynolds number giving the ratio of inertia force to viscous force in a flow and
frequently defined by:

VD
Re =


where, ρ = density of fluid (kg/m3) and μ is the molecular (laminar) viscosity of fluid (Pa.s)
Equation (1) may also be rearranged as

32 LV  16  L V 2 ' L V

2
hf = = 4   = 4 f (2)
 gD 2  VD  D 2 g D 2g

In equation (2), f’ʹis the Fanning friction factor given by

16 16 1
f'= = = f
VD Re 4

Both Darcy-Weisbach (f) and Fanning friction factors (f ʹ) are either read from Moody diagram
or calculated using various correlations such as Colebrook equation.

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Experiment 1(a)
Verification of Bernoulli’s Equation

OBJECTIVES
The objective of the experiment is to verify Bernoulli’s equation by demonstrating the relationship
between pressure head and kinetic head

Apparatus
i. Bernoulli’s apparatus is used to examine the flow of water through a two-
dimensional Perspex convergent-divergent passage of rectangular cross-section
with piezometer tubes along its length
ii. A constant level inlet tank to maintain a steady flow and a variable head outlet tank
with a control valve
iii. Discharge collection bucket
iv. Stopwatch
v. Platform scale

Schematic Diagram of Experimental Set-up

Figure 1.1: Experimental setup of verification of Bernoulli’s equation

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Procedure
i. The cross-sectional areas of the channel below the piezometer tubes are measured.
ii. A sheet of paper is placed at the back side of the piezometer tubes.
iii. Set up the apparatus to give a differential head between inlet and outlet tanks.
iv. The flow steadiness is obtained by adjusting the valves. When steady flow occurs the water
heads in the piezometer tubes remain constant.
v. The water heads in the inlet and outlet tanks and also the height of the water level in the
piezometer tubes are recorded on the paper sheet.
vi. Now water is collected in a bucket for a particular time. Then the weight of the bucket and
water is noted from the platform scale.
vii. Take a number of observations by varying the rate of discharge of water.

Data Collection
(Use γwater = 9810 kg/m3)

Table 1: Data collection for measuring flow rate

Weight of Weight of Time of Flow rate,

Observation Weight of
bucket filled water collection of W
No empty bucket Q = (m3/s)
with water collected, W water, t (sec) t
1
2
3
4
5
6
7
8
9

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Calculation
Table 2: Calculation for estimating total head

Cross- Velocity, Velocity Piezometer Total head,

Tube sectional Q V2 P P V2
V= head, head, + Z , H= +Z +
position area, A A 2g   2g
(m2) (m/s) (m) (m) (m)
1
2
3
4
5
6
7
8
9

Sample Calculations:
Observation no:
1. Cross sectional area, A =

Q
2. Velocity, V = =
A

V2
3. Velocity head, =
2g

P
4. Piezometer head, +Z =


P V2
5. Total head, H = + Z + =
 2g

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Graphical Presentation of Result
Plot the hydraulic gradient and total energy gradient lines. The closeness of total energy at different
sections in the channel implies the validity of Bernoulli’s equation although it is theoretically valid
for steady and ideal flow conditions.

Discussions
The following points need to be addressed accordingly-

• Variation of the total energy line along the flow

• Effect of friction
• Sources and effects of errors in measurements
• Sources and effects of the deviations in calculations
• Improvements required to reduce the discrepancies

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 (b)

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 Experiment No. 2
(a) Study of flow meters
(b) Study of minor losses
Experiment Outcomes
The objective of this experiment is to make students familiar with different types of flow meters
and understand the minor losses in a fluid flow. On completion of the experiment, the students
should be able to
1. Understand the principle of flow measurement in a pipe flow
2. Calibrate flow meters such as orifice meter
3. Determine the K factor for sudden contraction

Principles of flow measurement:

There are many types of flow meters: turbine-type flow meter, rotameter, orifice meter, and
venturi meter, etc. In turbine flow meters, a rotor is placed in a flow. The rpm of the rotor varies
with flow rate and by measuring the rpm, the flow rate is determined. Rotameters are suitable for
measuring flow rate through a vertical pipe. The location of the float in a rotameter depends
on the flow rate. Thus, the flow rate is determined by measuring the vertical displacement of
the float. The orifice meter is known as pressure-based flow meter (obstruction type). This
meter reduces the flow area and creates pressure differential which depends on flow rate. Thus,
flow rate is determined by measuring the pressure drop.

Minor loss:
Minor losses in a pipe flow come from the change in flow area and (or) direction by different
types of fittings. Pipe fittings are always required to complete a hydraulic piping system; for
example - sudden contraction, sudden expansion, valves, reducers, bends, elbows, crosses, T-
joints, etc. Some of them are shown in figure below:

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Data Collection
Given Data:
Pipe diameter, D1 =
Orifice diameter, D0 =
Room Temperature, Tr =
Rotameter absolute pressure, PR = 1000 mm Aq G
Rotameter absolute temperature, TR = 303 K

Experimental Data:
Specific weight of mercury =
Specific weight of water =
Specific weight of air =
Table 1: Manometer and Rotameter readings

Manometer reading
Air temp. inside the pipe, Ta (˚C)

Flow rate from rotameter, QR,

flow pressure in the pipe across the orifice
(Hg manometer) (water manometer)
No. of Observation

Hm, O (mm of water)

Right column (mm)

Right column (mm)

(m3/min)
Hm, Hg (mm of Hg)
Left column (mm)

Left column (mm)

Net deflection

Net deflection

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 5
4
3
2
1
No. of No. of Observation

5
4
3
2
1

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Observation

Air temp. inside the pipe, Ta (˚C)

Pa
(Pa)
Left column (mm)
Ta

Calculation and Result

(K)
Right column (mm)
Ρa
(kg/m3)
(Hg manometer)

Net deflection
flow pressure in the pipe

Hm, Hg (mm of Hg)

Actual flow rate
Qa (m3/s)

Left column (mm)

V21/2g
Manometer reading

(m of H2O)
Right column (mm)
V2 2/2g
(m of H2O)
(water manometer)

Net deflection
across the contraction

Table 5: Determination of K factor for sudden contraction Hm, C (mm of water)

Table 4: Manometer and Rotameter readings for pipe fittings

hL, contraction

Flow rate from rotameter, QR,

K factor (m3/min)

20
 6.

7.

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Experiment No. 3
Study of Flow through a Circular Pipe

EXPERIMENT OUTCOMES
The objective of this experiment is to demonstrate the velocity variation at throat and different
radii of a circular pipe when air flows through that pipe. On completion of the experiment, the
students should be able to
• Understand physical description of internal flow and the velocity boundary layer.
• Visualize the velocity distribution around a circular pipe due to the fluid flow.
• The concept of laminar and turbulent flow in a circular pipe.

FLOW THROUGH A CIRCULAR PIPE

Concept of Velocity Boundary layer
For an internal flow as such the current study, when a fluid enters a circular pipe at a uniform
velocity, the fluid particles at the boundary of the pipe come to a complete rest because of the no-
slip condition. As a result, the fluid particles in the adjacent layers slow down gradually due to
friction. To keep the mass flow rate through the pipe constant, the velocity of the fluid at the
midsection of the pipe increases to make up for the velocity reduction. Thus, a velocity gradient
develops along the pipe. The region of the flow in which the effects of the viscous shearing forces
caused by fluid viscosity are felt is called the velocity boundary layer. The hypothetical boundary
surface divides the flow in a pipe into two regions: the boundary layer region, in which the viscous
effects and the velocity changes are significant, and the inviscid (core) flow region, in which the
frictional effects are negligible and the velocity remains essentially constant in the radial direction.
The region from the pipe inlet to the point at which the boundary layer merges at the centerline is
called the hydrodynamic entrance region.

The region beyond the entrance region in which the velocity profile is fully developed and remains
unchanged is called the hydrodynamically fully developed region. The velocity profile in the fully
developed region is parabolic in laminar flow and somewhat flatter (or fuller) in turbulent flow
due to eddy motion and more vigorous mixing in the radial direction. However, in fluid flow, it is
convenient to work with an average velocity Vav, which remains constant in incompressible flow

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when the cross-sectional area of the pipe remains constant and fluid properties evaluated at some
average temperature are also treated as constants.

Criteria:
Fluid flow regime is mainly characterized by the ratio of inertial forces to viscous forces in the
fluid. This ratio is called the Reynolds number and is expressed for internal flow in a circular pipe
as
𝑖𝑛𝑡𝑒𝑟𝑡𝑖𝑎 𝑓𝑜𝑟𝑐𝑒 𝜌𝑉 𝐷
𝑅𝑒 = =
𝑣𝑖𝑠𝑐𝑜𝑢𝑠 𝑓𝑜𝑟𝑐𝑒 𝜇
where Vav = average flow velocity (m/s), D = characteristic length of the geometry (diameter in
this case, in m), and µ/ρ = kinematic viscosity of the fluid (m2 /s).
As a general criterion, for flow through smooth pipes,
Re < 2300 signifies the flow to be laminar
Re > 4000 signifies the flow to be turbulent.
At large Reynolds numbers, the inertial forces are large relative to the viscous forces, and thus the
viscous forces cannot prevent the random and rapid fluctuations of the fluid. At small or moderate
Reynolds numbers, however, the viscous forces are large enough to suppress these fluctuations
and to keep the fluid “in line.” Thus, the flow is turbulent in the first case and laminar in the second.

ABOUT THE EXPERIMENT

In this experiment, ambient air driven primarily by a pressure difference is passed through a
parabolic nozzle to the circular pipe. Velocity of the flowing fluid at the throat of the parabolic
nozzle is then calculated from the manometric deflection of the water manometer (For the constant
operating speed of 3800 rpm). Further down the circular pipe a pitot traverse is located in a perspex
box. Linear distance travelled by the traverser after each full revolution represents the radial
location in the circular pipe and a corresponding manometric deflection is obtained from the
inclined water manometer connected to the pitot tube. Thus, velocity profile in circular pipe is
obtained.

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Study of flow through a circular pipe

OBJECTIVES

The objectives of the experiment are to

i) To measure the velocity of flowing fluid

 At the throat of the inlet nozzle
 At various radii of the circular pipe.
ii) To find the flow rate of flowing fluid.
iii) To compare the discharge obtained graphically (V vs r2) with that obtained through
the parabolic nozzle.

APPARATUS

Apparatus used in this experiment are:

i) A smooth long pipe

ii) A parabolic nozzle at the inlet of the pipe
iii) A suction fan at the outlet of the pipe
iv) Three (air-water) manometers one at nozzle and other at pitot tube
v) Pitot tube with traverse mechanism
vi) Static pressure tube at various distances

EXPERIMENTAL SET UP

Figure: Experimental set-up of flow through a circular pipe

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DATA COLLECTION
Given Data:
Nozzle throat diameter = 2 inch = 5.08 *10-2 m
Pipe diameter = 3.1 inch = 7.87*10-2 m
Pitot tube diameter = 1.2*10-2 m
Linear distance travelled by the traverser after one full revolution= 0.1 inch = 2.54 mm
Co-efficient of discharge of the nozzle, Cd = 0.98
Universal gas constant, R = 287 Nm/KgK
Barometric pressure, P (Pa) =
Room temperature, T (K) =
Density of air, ρair (kg/m3) =
Viscosity of air, µair (N.s/m2) =
Specific weight of water γw (N/m3) =

Experimental Data:
Table 1. Data for Velocity of Flowing Fluid at the Throat of the Parabolic Nozzle (For the constant
operating speed of 3800 rpm)

Manometric Deflection, Hw Velocity of Air, Vth

Observation Position
(m of water) (m/s)
Throat

Table 2. Data for Velocity Profile in Circular Pipe (Measuring with pitot tube)

Radial Manometric
No. of No. of r2 Velocity of Air
Location ,r Deflection,
Observations Revolutions (mm2) (m/s)
(mm) (m of water)
1
2
3
4
5
6
7
8
9

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 10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29

CALCULATIONS AND RESULTS

Sample Calculation:
Observation no.
Manometric deflection, Hw (m of water), at throat =
Manometric deflection, Hw (m of water), using pitot tube =

∆
Throat velocity, Vth = = =

( .)
Nozzle throat cross-sectional area, Ath = 𝜋 =

Flow rate of nozzle, Qnozzle = Cd * Ath* Vth

=

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Velocity at a radial location , Vr= =

Discharge obtained graphically, Qgraph = π * area under the curve (V vs r2)

= (using Trapezoidal rule)
=
( .)
Cross sectional area of the pipe, Ap == 𝜋 =

Average velocity, Vav = =

Reynolds number, Re= =

% of error in flow rate = * 100% =

GRAPHICAL PRESENTATION OF RESULTS

i) Plot the velocity profile along the radius of the circular pipe (r vs V).

DISCUSSION

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 Experiment no. 4(a)

Name of the Experiment: Study and Performance test of a Pelton

Wheel.

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Objectives:

 To study the working principle of a Pelton wheel.

 To determine the performance parameters of the Pelton wheel.
 To plot efficiency vs speed, discharge vs speed, Pout vs Speed, efficiency vs Pout curve of a
Pelton wheel.
 To calculate the specific speed of a Pelton wheel.

Apparatus:

Schematic diagram:

C
B
D

A=
E
B=

C=

D=

E=

Fig. Experimental set up of performance test of a Pelton wheel.

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Data from the experiment:

Speed of the Pelton

Manometer Reading Spring
No. wheel (N)
Scale Force, F
of Net
Left (L) Right (R) Reading (N)
obs. Deflection rpm Rad/s
inch inch (Kg)
(inch)

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Data Obtained from calculation:

No. Torque Power Pressure Discharge Efficiency

of (T) output Head (Q) (η)%
obs. Nm ( Po) (h) (Cusec ×
Watt m 102)
m 3/hr

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Sample calculations:

Dynamometer wheel radius, r = 4 inch = m

Pressure Head correction, Z = 1.1 m

Pelton wheel rotor radius, R =

Pelton wheel speed, N = rpm

2𝜋𝑁
ω= rad/s
60

Torque, T = F×r Nm

Output power, Po = Tω

Pressure head,h= P/γ psi + Z (m)

= (P×144/62.4)/3.28 +Z (m)

Discharge, Q = 0.024×√(L+R) cusec

= m3/hr

Input hydraulic Power, Pi = ϒQh

𝑃𝑜
Efficiency, η = × 100 %
𝑄ϒ𝐻

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 𝜔𝑅(𝑝𝑒𝑟𝑖𝑝ℎ𝑒𝑟𝑎𝑙 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑜𝑓 𝑟𝑜𝑡𝑜𝑟)
Speed ratio, φ =
𝐶𝑣 √2𝑔ℎ(𝑓𝑙𝑢𝑖𝑑 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑎𝑡 𝑛𝑜𝑧𝑧𝑙𝑒 𝑡𝑖𝑝)

𝑁√𝑃𝑜𝑢𝑡
Specific Speed, Ns = where, N (rpm), Pout (KW), H(m)
𝐻 5/4

 Plot the characteristic curve of the Pelton wheel.

Discussion:

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 4(b)

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 Fig.1 :

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Objectives:
1. To observe different components of a hermetically sealed compressor.
2. To understand the working principal of these parts and identify them.

Report Writing:
1. Identify and write down the function of the various components of the hermetically
sealed compressor shown in the lab.
2. Differentiate between components of figure no. 01 and the hermetically sealed
compressor shown in lab.
3. Find out any missing components of hermetically sealed compressor that you think
should be there in lab.

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 Experiment no. 5(a)
Name of the experiment: Performance test of a centrifugal pump

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 Experiment no. 5(a)
Name of the experiment: Performance test of a centrifugal pump

Objectives:
To study the performance characteristics of the pump at constant speed when varying the
flowrate.

Apparatus:

Schematic diagram:

Figure 5(a): Schematic Diagram of Centrifugal Pump Test

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 Data Collection:

Operating speed, N = rpm

Suction pipe dia. ds = m

Delivery pipe dia. dd = m

Suction Delivery
Pressure, Pressure, Manometer reading
Flow
No hg, s hg, d Total Head rate,
of
(m of H2O) Q
Obs. Net
inch m of m of Left, L Right, R (m3/s)
Kg/cm 2 deflection,
Hg H2 O H2 O (cm) (cm)
∆H (m)

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 Calculation:

Manometer Net Deflection, ∆𝐻 = L + R = (cm)

= (m)

Flow rate, Q = 0.015 × √∆𝐻 (m3/s) =

Here,
Pressure gauge reading in suction side, hg, s =
Pressure gauge reading in delivery side, hg, d =
hs = vertical distance of the pressure gauge in the suction side from the pump horizontal
centerline = Zs = m
hd = vertical distance of the pressure gauge in the delivery side from the pump horizontal
centerline = Zd = m
Q
Velocity at the suction side, vs 
 d s2
4

Q
Velocity at the delivery side, vd 
 d d2
4

 vd2   vs2 
Total Head, H t   hg , d   hd    hg , s   hs 
 2g   2 g 

Input Power, Pi =

Output Power, Po  Q H t

Po
Efficiency,    100%
Pi

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 Calculation Table:

Total head, Input power, Output

Obs. N Discharge, Q Efficiency,
H Pi power, Po
No. (rpm) (m3/s) η
(m) (Watt) (Watt)

Discussions:
(Discuss the experimental pump characteristic curve. Also, compare it with ideal pump characteristic
curve. Discuss the possible source of deviations in your results.)

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 Experiment no. 5(b)
Name of the experiment: Study of centrifugal pumps in series and parallel
connection

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 Experiment no. 5(b)
Name of the experiment: Study of centrifugal pumps in series and parallel connection

Objective:
To study the flow rate and head characteristics of two centrifugal pumps in series and parallel
connections.

Apparatus:

Schematic diagram (connection circuit):

Pump 2 off and Pump 1 running Pump 1 off and Pump 2 running

Both pumps in series connection Both pumps in parallel connection

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 Data collection:

For pump 2 off pump 1 running:

Suction Delivery
Pressure, Pressure, Manometer reading
Flow
No Ps ,1 Pd, 1 Total Head rate,
of
(m of H2O) Q
Obs. Net
inch m of m of Left, L Right, R (m3/s)
Kg/cm 2 Deflection,
Hg H2 O H2 O (cm) (cm)
∆H (m)

For pump 2 off pump 1 running:

Suction Delivery
Pressure, Pressure, Manometer reading
Flow
No Ps ,2 Pd, 2 Total Head rate,
of
(m of H2O) Q
Obs. Net
inch m of m of Left, L Right, R (m3/s)
Kg/cm 2 Deflection,
Hg H2 O H2 O (cm) (cm)
∆H (m)

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 For pumps is series connection:

Suction Delivery
Pressure, Pressure, Manometer reading
Flow
No Ps ,3 Pd, 3 Total Head rate,
of
(m of H2O) Q
Obs. Net
inch m of m of Left, L Right, R (m3/s)
Kg/cm 2 Deflection,
Hg H2 O H2 O (cm) (cm)
∆H (m)

For pumps is parallel connection:

Suction Delivery
Pressure, Pressure, Manometer reading
Flow
No Ps ,4 Pd, 4 Total Head rate,
of
(m of H2O) Q
Obs. Net
inch m of m of Left, L Right, R (m3/s)
Kg/cm 2 Deflection,
Hg H2 O H2 O (cm) (cm)
∆H (m)

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 Calculation:

1. Suction pressure, Ps = (inch Hg)

= (m of H2O)

2. Delivery pressure, Pd = (kg/cm2)

= (m of H2O)

3. Total head = Pd – Ps = (m of H2O)

4. Manometer net deflection, ∆𝐻 = L + R = (cm)

= (m)
5. Flow rate, Q = 0.015 × √∆𝐻 (m3/s) =

Discussion:

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 Experiment No. 6(a)

Name of the Experiment: Study and performance test of a submersible

pump

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 Experiment No. 6(a)
Name of the Experiment: Study and performance test of a submersible pump

Objectives:
• To study the working principle of a submersible pump.
• To determine the performance parameters of a submersible pump.
• To plot the characteristic curve of a submersible pump and find its duty point.
• To calculate the specific speed of a submersible pump.

Apparatus:

Schematic diagram:

Figure 6(a): Schematic diagram of a submersible pump test

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 Experimental measurement data:

Datum Head of the PG (Pressure Gauge), H0 = (m)

PG calibration Equation:
Flowmeter calibration equation:
Wattmeter calibration equation:

No. Flow meter reading Pressure gauge Input power, Pin

of reading Wattmeter reading
Obs. Vol (lit) Time (s) (Psi) (kW)

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 Calculated data:

Flow rate/discharge, Q Overall

Output
No. of Head, H Input power, efficiency,
power, Pout
Obs. lit/min m3/s (m) Pin η
(kW)
(lpm) (cumec) (kW) (%)

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 Sample calculation:

1. Discharge, Q = vol/time = lit/s

= lit/min
Actual discharge, Q = lit/min [use calibration equation]
Actual discharge, Q = m3/s

p
2. Head, H =  H0 = m of Water [use calibration equation]


3. Input Power, Pin = kW [from Wattmeter]

Actual Input Power, Pin = kW [use calibration equation]

4. Output power, Pout = QH kW

Pout
5. Overall efficiency, η =  100 %
Pin

N Q
6. Specific speed (at best efficiency point), Ns =
H34

Graphical presentation:

Plot the characteristics curve of a submersible pump (H, Pin, η vs. Q) and find its duty point at
maximum efficiency, ηmax.

ME 224 51
 Experiment No. 6(b)

Name of the Experiment: Dismantling and assembling of a centrifugal

pump

ME 224 52
 Experiment No. 6(b)
Name of the Experiment: Dismantling and assembling of a centrifugal pump

Introduction:

Centrifugal pumps are devices that are used to transport fluids by the conversion of rotational
kinetic energy to the hydraulic energy of the fluid flow. The kinetic energy typically comes
from an electric motor. Centrifugal pumps are used in more industrial applications than any
other kind of pumps.

Working principle:

Fluid enters the pump axially through the suction pipe to the eye of impeller (low pressure area)
which rotates at high speed. As the impeller blades rotate, they transfer momentum to incoming
fluid. The fluid accelerates radially outward, and a vacuum is created at the impellers eye that
continuously draws more fluid into the pump. As the fluid’s velocity increases its kinetic
energy increases. Fluid of high kinetic energy is centrifugally forced out of the impeller area
and enters the volute. In the volute, the fluid flows through a continuously increasing cross
sectional area, where the kinetic energy is converted into fluid pressure according to
Bernoulli’s principle. The main parts of a centrifugal pump include the suction pipe, impeller,
volute casing, shaft, packing seals, bearing etc. The impeller may be open, semi open, or closed
type depending on the fluid to be handled.

Activities:

1. Dismantle a centrifugal pump using the tools provided.

2. Identify and observe each of the components.
3. Take photographs of various components and attach them with the report.
4. Study the components and energy flow sequence.
5. Assemble all components to form the pump again.

Figure 6 (b): Centrifugal pump and its components.

ME 224 53
 Pump Components Sequence:

Suction
Pipe

Shaft

Energy Conversion Sequence:

220 V AC
Input

Question and answer:

1. Where are the gaskets placed?

2. Why gland packing seals are used?

ME 224 54
 Experiment No. 7
Name of the Experiment: Study and performance test of a
positive displacement pump

ME 224 55
 Experiment No. 7
Name of the Experiment: Study and performance test of a positive displacement pump

Objective:
To find the pump performance for a range of delivery pressures (varied load) at a constant
speed.

Apparatus:

Experimental Setup:

Pressure, Temperature,
and Flow meter
Universal
Dynamometer

Oval Gear Flow

Meter

Oil
Piston Pump
Reservoir

Figure 7(a): Positive displacement pump module

ME 224 56
 Figure 7(b): Schematic diagram of piston pump setup

Piston Pump Working Action Piston Pump (TQ MFP103a)

Figure 7(c): Piston pump

ME 224 57
 Experiment: 7(a)
Experiment Name: Effect of delivery pressure at constant speed

ME 224 58
 Experiment: 7(a)
Experiment Name: Effect of delivery pressure at constant speed

Objective:
To find the pump performance for a range of delivery pressures (varied load) at a constant
speed.

Procedure:

o Fit the pump according to the instructions (i.e., video).

o Fully open inlet and delivery valves.

o Use button on the pressure display to zero all the pressure readings.

o Zero the torque reading of the MFP100 Universal Dynamometer.

o Press the start button on the Motor Drive and run the speed to 1600 rpm (+/- 5 rpm) for
at least five minutes and monitor the oil temperature until it stabilizes. Check that any
air bubbles have moved away from the flowmeter.

o Record the speed and oil temperature.

o Slowly shut the delivery valve and maintain the speed until the delivery pressure
reaches 2 bar. Allow a few seconds for conditions to stabilize. Record the indicated
flow and pressures.

o Continue increasing the delivery pressure in 1 bar steps (while keeping the speed
constant) to a maximum of 15 bar. At each step, allow a few seconds for conditions to
stabilize and record the indicated flow and pressures.

o (Optional) Repeat the test at two other lower speeds (1200 rpm and 800 rpm are
recommended)

ME 224 59
 Data from experiment:
Swept Volume, Vs = 0.00715 L/rev
Speed, NP = rpm,
Expected Flow = L/min
Oil Temperature, T1 = (at Start), (at end)

Data Table:

Obs. Delivery Inlet Pressure Pressure Flow Shaft Hydraulic Overall Volumetric
No Pressure Pressure Difference Difference Rate Power Power Efficiency Efficiency
P2 P1 (bar) ΔP, (Bar) ΔP, (Pa) Q v, WD, WP, ɳP ,(%) ɳv, (%)
(bar) (L/min) (W) (W)

1
2
3
4
5
6
7
8
9
10
11
12
13
14

ME 224 60
 Calculation:

1. Mechanical Power (into the pump), WD =

2. Hydraulic Power (from the pump), WP = (P2 - P1) Qv =

3. Overall Pump Efficiency, ηP =

4. Swept Volume VS =

5. Expected Volume Flow rate = VS × Np =

6. Volumetric Efficiency, ηV = Qv /(VS × Np)×100 =

Discussion:

 Compare the Flow rate, Shaft power, Volumetric efficiency, and Overall efficiency
with Pressure difference.

 Create one chart with two vertical axes, one for flow rate and other one for volumetric
efficiency, overall efficiency, and shaft power.

 Discuss the individual parameters behavior with the change of pressure difference.

 If the test is run at other speeds, repeat the above discussions, and compare them.

ME 224 61
 Experiment: 7(b)
Experiment Name: Effect of speed at constant speed delivery pressure

ME 224 62
 Experiment: 7(b)
Experiment Name: Effect of speed at constant speed delivery pressure

Objective:
To find the pump performance for a range of speeds at a constant delivery pressure (load).

Procedure:

o Fit the pump according to the instructions (i.e., video).

o Fully open inlet and delivery valves and use button on the pressure display to zero all
the pressure readings.

o Zero the torque reading of the MFP100 Universal Dynamometer.

o Press the start button on the Motor Drive and run the speed to 1600 rpm (+/- 5 rpm) for
at least five minutes and monitor the oil temperature until it stabilizes.

o Wait for any trapped air bubbles to move from the flowmeter.

o Slowly shut the delivery valve and maintain the speed until the delivery pressure
reaches 15 bar.

o Allow a few seconds for conditions to stabilize. Record the speed, oil temperature, the
indicated flow (from display) and pressures.

o Reduce the speed by 100 rpm while adjusting the delivery pressure to keep it constant
at 15 bar. Allow the conditions to stabilize and record the indicated flow and pressures.

o Continue decreasing the speed in 100 rpm steps (while keeping the pressure constant)
until you reach 800 rpm. At each step, record the indicated flow and pressure.

o (Optional) Repeat the test at two other fixed delivery pressures (10 bar and 5 bar are
recommended).

ME 224 63
 Data from experiment:
Swept Volume, Vs = 0.00715 L/rev
Delivery Pressure, P2 = bar
Oil Temperature, T1 = (at start), (at end)

Data Table:
Obs. Speed, Inlet Pressure Flow Expected Shaft Hydraulic Overall Volumetric
No NP Pressure Difference rate Flow, Power Power Efficiency Efficiency
(rpm) P1, ΔP, (Pa) Qv, (L/min) WD, WP, ɳP ,(%) ɳv, (%)
(bar) (L/min) (W) (W)

1
2
3
4
5
6
7
8
9

ME 224 64
 Calculation:

1. Mechanical Power (into the pump), WD =

2. Hydraulic Power (from the pump), WP = (P2−P1) Qv =

3. Overall Pump Efficiency, ηP =

4. Swept Volume VS =

5. Expected Volume Flow rate = VS × Np =

6. Volumetric Efficiency, ηV = Qv / (VS × Np) × 100 =

Discussion:

 Compare the Flow rate, Shaft power, Volumetric efficiency, and Overall efficiency
with Pump speed.

 Create one chart with two vertical axes, one for flow rate and other one for volumetric
efficiency, overall efficiency, and shaft power.

 Discuss the individual parameters behavior with the change of pump speed.

 If the test is run at other delivery pressures, repeat the above discussions, and compare
them.

ME 224 65
 Experiment: 7(c)
Experiment Name: Effect of inlet pressure on pump performance

ME 224 66
 Experiment: 7(c)
Experiment Name: Effect of inlet pressure on pump performance

Objective:
To show how reduced inlet pressures affect pump performance and cause cavitation.

Procedure:

o Fit the pump according to the instructions (i.e., video).

o Fully open inlet and delivery valves.

o Use button on the pressure display to zero all the pressure readings.

o Zero the torque reading of the MFP100 Universal Dynamometer.

o Press the start button on the Motor Drive and run the speed to 1600 rpm (+/- 5 rpm) for
at least five minutes and monitor the oil temperature until it stabilizes.

o Wait for any trapped air bubbles to move from the flowmeter.

o Slowly shut the delivery valve and maintain the speed until the delivery pressure
reaches 2 bar.

o While keeping the speed and delivery pressure constant, use the inlet valve to reduce
the inlet pressure to the nearest 0.1 bar.

o Allow a few seconds for conditions to stabilize, then record the speed, the oil
temperature, the indicated flow, and pressures.

o Continue decreasing the inlet pressure in 0.1 bar steps (while keeping the delivery
pressure and speed constant) until you can hear a change in sound from the pump
(cavitation). At each step, record the indicated flow and pressures.

ME 224 67
 Data from experiment:
Swept Volume, Vs = 0.00715 L/rev,
Pump Speed, NP = rpm,
Expected Flow = L/min
Delivery Pressure, P2 = bar
Oil Temperature, T1 = (at Start), (at end)

Data Table:

Inlet Pressure Flow Shaft Hydraulic Overall Volumetric

Obs. Pressure Difference rate Qv, Power Power Efficiency Efficiency
No P1, (bar) ΔP, (Pa) (L/min) WD, WP, ɳP ,(%) ɳv, (%)
(W) (W)

ME 224 68
 Calculation:

1. Mechanical Power (into the pump), WD =

2. Hydraulic Power (from the pump), WP = (P2 - P1) Qv =

3. Overall Pump Efficiency, ηP =

4. Swept Volume VS =

5. Expected Volume Flow rate = VS × Np =

6. Volumetric Efficiency, ηV = Qv / (VS × Np) × 100 =

Discussion:

 Compare the Flow rate, Shaft power, Volumetric efficiency and Overall efficiency with
inlet pressure.

 Create one chart with two vertical axes, one for flow rate and other one for volumetric
efficiency, overall efficiency and shaft power.

 Discuss the individual parameters behavior with the change of pump speed.

 Comment on how low the inlet pressures (that can cause cavitation) affect the
performance of the pump.

ME 224 69