TITLE :
Performance of pump OBJECTIVE :
To obtain and analyze the performance characteristics of centrifugal pump operating at a given impeller speed. INTRODUCTION :
A pump is a device device used used to move gases, liquids liquids or slurries. slurries. A pump moves moves liquids or gases from lower pressure to higher pressure, and overcomes this difference in pressure by adding energy to the system. A gas pump is generally called a compressor, except in very low pressure-rise applications, such as in heating, ventilating, and airconditioning, where the operative equipment consists of fans or blowers. A centrifugal pump is a rotor dynamic pump that uses a rotating impeller impeller to increase the velocity of a fluid. entrifugal pumps are commonly used to move liquids through a piping system. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, impeller, flowing radially outward into a diffuser or volute chamber, from where it exits exits into into the downst downstrea ream m piping piping syste system. m. ent entrif rifug ugal al pumps pumps are used used for large large discharge through smaller heads.
!xample of entrifugal Pump
A centrifugal pump converts rotational energy, often from a motor, to energy in a moving fluid. A portion of the energy goes into "inetic energy of the fluid. #luid enters axially through eye of the casing, is caught up in the impeller blades, and is whirled tangentially and radially outward until it leaves through all circumferential parts of the impeller into the diffuser part of the casing. The fluid gains both velocity and pressure while passing through the impeller. The doughnut-shaped diffuser, or scroll, section of the casing decelerates the flow and further increase the pressure. A centrifugal pump wor"s by the conversion of the rotational "inetic energy, typically from an electric motor or turbine, to an increased static fluid pressure. This action is described by $ernoulli%s principle. The rotation of the pump impeller imparts "inetic energy to the fluid as it is drawn in from the impeller eye and is forced outward through the impeller vanes to the periphery. As the fluid exits the impeller, the fluid "inetic energy is then converted to pressure due to the change in area the fluid experiences in the volute section. Typically the volute shape of the pump casing, or the diffuser vanes are responsible for the energy conversion. The energy conversion results in an increased pressure on the downstream side of the pump, causing flow.
THEORY :
The centrifugal pump belongs to a family of turbo machines which is distinguished as an energy absorbing device. The performance characteristics of a typical centrifugal pump are governed mainly by the following parameters& pump head ', water horsepower
PW
, bra"e horsepower bhp, efficiency (, and flow rate ) for a
given impeller speed *. The pump head ' is termed as the amount of energy measured in head added by the pump to the fluid. +n this experiment, the observed data used to calculate this parameter is given as
( P − P ) 1
H= P1
And
P2
2
pg
are the delivery and inta"e pressure of the pump, respectively.
The water horsepower
Pw
is power received by the fluid from the pump and is given
by the following relation& Pw = p gHQ
The bra"e horsepower bhp to the pump can be regarded as the shaft power produced by the electric motor. An appropriate relation used for calculating this parameter using the observed data is given as&
Bhp=Tω=T(2πN) Ttorque, angular speed, *pump rotational speed in revolution per second rps/. The pump overall efficiency ( for a given impeller size and speed is defined as &
P w
η = bhp
PROCEDURES :
0. 1alve labeled 12 was made sure initially closed. 3. 4otor speed were ensured to set maximum by turning the speed controller fully cloc"wise. 5. 4ain power supplied and main switched were turn on at the control panel. 6igital indicators were ensured illuminated. 7. Then pump were turned on and valve labeled 12 was open until the flow rate reached 38 9P4. 2. All relevant measurements were recorded when the system has stabilized. :. The flow rate were increased with increment of 08 9P4 until the flow rate reaches ;8 9P4 and repeated.
RESULT :
#T0
#+0 9P4/
9P4/
=P4/
38 58 78 28 :8 B8 8 ;8
0; 37 5 28. :8 B8 B ;
3
0:: 0:2 0:58 02;: 02:5 023: 0283 07BB
3
#T0 m / s
#+0 m / s
/ 5.557
/ 5.0:B
× 10
−4
2.888 × 10
−4
−4
×10
−3
0 × 10
×10
?ATT/
@/
@/
0BB 0;5 0; 30: 358 357 35; 37B
5.0; 5.02 5.00 5.82 3.;; 3.;3 3.B 3.0
P>?!=?ATT/
0BB
5.87 3.;5 3. 3.8 3.:8 3.:; 3.2 3.7
P+0 kgf / cm
/ 8 8 8 8 8 8 8 8
P+3 2
/ 3.0 3.8 0.; 0.B 0.2; 0.7 0.3 0.85
PT0
PT3
P+0
P+3
@/
@/
"Pa/
"Pa/
5.0;
5.87
8
382.;7
0;5
5.02
3.;5
8
0;:.05 :
−4
0B8.:;5
0;
5.00
3.
8
0:.53 ;
−4
0:B.055
30:
5.82
3.8
8
0B7.2: 0
−4 −3
2
5 0B5.:32
0 × 10
kgf / cm
−4
.7:B
−4
PT3
0B:.22
:.555
.555 × 10
×10
PT0
/
7.888
:.::B × 10
×10
P>?!=
0:5.:BB
358
3.;;
3.:8
8
022.;3
0.0:B
0.0:B
−3
02;.83
357
3.;3
0.72
−3
05B.3; 2
× 10
0.557
02B.3;
35;
3.B
3.2
8
00B.:0
027.:B0
37B
3.0
3.7
8
080.80
−3
× 10
× 10 −3
0.2 × 10
0.:55
8
−3
× 10
P?
T *m/
?ATT/ 38.;;7 0;.;;7 0.;;7 0B.B;2 02.;2 05.;;: 00.;;: 08.3;B
8
−3
× 10
' m/
3.:;
:.::3 ;.8: 037.335 072.7:7 022.;32 0:8.332 02:.;0 020.20:
5.B02 2.5;: :.;25 .502 ;.083 ;.2B; ;.252 ;.52;
$'P
!##+!*C
?ATT/
@/
7030.333 2:.2;7 B72B.8:5 B50.00 ;5:8.:07 ;:0B.;77 ;735.300 ;8;2.532
0.:B 0.:B 0.:B 0.:B 0.:B 0.:B 0.:B 0.:B
*ote& #low rate, ) used is #T0 values to find water horsepower and bra"e horsepower .
SAMPLE OF CALCULATIONS:
6ensity >f ?ater& ;;;.;B "gDmE 3
0 9P4 0.:::::::B F 08 -2 m / s
•
Pump 'ead, '.
'
P 1− P 2 ρg
PI 2 − PI 1 ρg
( 205.943 −0 ) × 10 '38 ( 999.97 )( 9.81)
3
38.;;7 m •
'orsepower, P w. PW = ρgHQ
PW 20
=999.97 × 9.81× 20.994 ×3.334 × 10−
PW 20=¿
•
:.::3 ?
$ra"e 'orsepower, bhp. bhp T 3G*
P w × 9.554
T
N
68.662
T38
−9.554
176.558
5.B02 *m
bhp/ 38 5.B02 F 3G F
176.558
7030.333 ?
•
Pump !fficiency, (. P w
(
bhp F 088 @
4
68.662
(38
4121.222
F 088 @
0.:B @
Graph Of Brake Head Pump(H) Vs. Flow Rate(Q) 25 20 15 10 5 0
H (m)
Q (^3∕)
Graph Of Brake Horsepower(bhp) Vs. Flow Rate(Q) 12000 10000 8000 6000 4000 2000
bhp(watt)
0
Q (^3∕)
Graph Of !"#e$"%(&) Vs. Flow Rate(Q) 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0
!"#e$"% (&)
Q (^3∕)
Muhammad Izzuddin Arif Bin Abdul Samad 20132!"33 DISCUSSION.
The experiment is conducted to determine centrifugal pump performance characteristic by for several set of speed centrifugal pump. After collected all the date and calculated. ?e computed all the data that have been recorded, we obtained 5 different graph. The result of the experiment, we can see that for the graph $ra"e 'ead Pump '/ vs. #low =ate )/, the graph is gradually decreased as the flow rate increased. The highest reading for bra"e head pump is 38.;;7 m. #or the graph $ra"e 'orse Power $'P/ vs. #low =ate )/, we see that the graph is steadily increased as the bra"e horsepower and flow rate increased. The highest reading for bra"e horsepower is ;:0B.;77 ?att. Then, for the graph of !fficiency vs. #low =ate, the readings are constant. There is no increase or decrease in line of graph. The efficiency is 0.:B@. There are slightly difference between the theoretical value and experiment value. The problem may come from the error during the experiment. ?e need to "eep in mind
that this is an experiment and the value could not be achieved due to some unavoidable factor such as the condition of the experiment where the apparatus is not in a good wor"ing condition and the experiment is conducted not under a standardize condition.
CONCLUSION.
As for the conclusion, the obHective of this experiment to obtain and analyses the performance characteristics of a centrifugal pump operating at a given impeller speed were successful. The conclusion that we are made the increasing of the flow rate ) will affect the pump head '/, $ra"e 'orse Power $'P/ and efficiency (/ of the pump. Although the theoretical value and experimental value are slightly difference because of our human errors such as parallax error and maybe in calculating process.
4uhammad Ammar #athi $in Iamaruzaman 3805;BB825/ 6iscussion& #rom The experiment and data collected, we have plotted 5 graph which are $ra"e head pump vs flow rate, $ra"e horse power vs #low rate and efficiency of the pump vs #low rate. #rom the graph bra"e head pump vs the flow rate, we can observed that the bra"e head pump was inversely proportional to the flow rate. This is may be because the higher the volume of the flow rate, the lower the pump power to generate head pump power. 6iffer from the previous graph, bra"e horse power is directly proportional to the flow rate of the water as we can observed from the second graph. #or the efficiency of the graph, we can state that the flow rate does not affect the efficiency of the pump as the pump flow in constant number of efficiency as the flow rate increased. There might be some error happen during the experiment as the result obtained was slightly error from its theoretical value. #irstly the flow rate of the water was unstable and hardly to control as we didnJt "now what is the exact number that the
digital gauge was showing. >ther than that, there might be some power loses during the pumping process occurs. +t might effect the value of data we have obtained and collected. =eccomendly, + would say that the systemJs valve and digital gauge of the flow rate need to be fix and specific to control the flow of the water to ma"e sure the flow rate was fixed and stable to be able to perform the experiment better.
onclusion& onclusively, we have obtained the result that we want and all three graphs was plotted to prove and show the pump performance +n the experiment. All the obHectives was reached and the experiment was succeed as we have obtained the pump performance with data and numbers that we have calculated.
REFERENCE :
0. http&DDcentrifugal-pump.blogspot.comD388;D80Dcentrifugal-pumpperformanceK8;.html 3. en.wi"ipedia.orgDwi"iDCentrif!"# K $%$ 3. http&DDwww.scribd.comDdocD333B8;D9ab-=eport-Performanceharacteristics-of-entrifugal-PumpLscribd
