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FACULTY OF CIVIL AND ENVIRONMENTAL ENGINEERING DEPARTMENT OF WATER & ENVIROMENTAL ENGINEERING WATER ENGINEERING LABORATORY
LAB REPORT Subject Code Code & Experiment Title Course Code Date Section / Group Name of Group Lecturer/Instructor/Tutor Received Date
Comment by examiner
BFC 21201 MKA – 04 ; SERIES AND PARALLEL PUMP TEST 2 BFF/1 5 DECEMBER 2011 5/2 MUHAMMAD IKHWAN BIN ZAINUDDIN (DF100018) 1. AFANDI BIN ABD WAHID (DF100122) 2.MOHD HASIF BIN AZMAN (DF100079) 3.MUHAMMAD HUZAIR BIN ZULKIFLI (DF100040) CIK AMNANI BIN ABU BAKAR EN JAMILULLAIL BIN AHMAD TAIB 12 DECEMBER 2011
Received
STUDENTS’ ETHICAL CODE (SEC) DEPARTMENT OF WATER & ENVIRONMENTAL ENGINEERING FACULTY OF CIVIL & ENVIRONMENTAL ENGINEERING UNIVERSITI TUN HUSSEIN ONN MALAYSIA BATU PAHAT, JOHOR
“I declare that I have prepared this report with my own efforts. I also declare not receive or give any assistance in preparing this report and make this affirmation in the belief that nothing is in, it is true”
………………………………………. (STUDENT SIGNATURE) NAME : MUHAMMAD IKHWAN BIN ZAINUDDIN MATRIC NO. : DF100018 DATE : 11 DECEMBER 2011
STUDENTS’ ETHICAL CODE (SEC) DEPARTMENT OF WATER & ENVIRONMENTAL ENGINEERING FACULTY OF CIVIL & ENVIRONMENTAL ENGINEERING UNIVERSITI TUN HUSSEIN ONN MALAYSIA BATU PAHAT, JOHOR
“I declare that I have prepared this report with my own efforts. I also declare not receive or give any assistance in preparing this report and make this affirmation in the belief that nothing is in, it is true”
………………………………………. (STUDENT SIGNATURE) NAME : AFANDI BIN ABD WAHID MATRIC NO. : DF100122 DATE : 11 DECEMBER 2011
STUDENTS’ ETHICAL CODE (SEC) DEPARTMENT OF WATER & ENVIRONMENTAL ENGINEERING FACULTY OF CIVIL & ENVIRONMENTAL ENGINEERING UNIVERSITI TUN HUSSEIN ONN MALAYSIA BATU PAHAT, JOHOR
“I declare that I have prepared this report with my own efforts. I also declare not receive or give any assistance in preparing this report and make this affirmation in the belief that nothing is in, it is true”
………………………………………. (STUDENT SIGNATURE) NAME : MOHD HASIF BIN AZMAN MATRIC NO. : DF100079 DATE : 11 DECEMBER 2011
STUDENTS’ ETHICAL CODE (SEC) DEPARTMENT OF WATER & ENVIRONMENTAL ENGINEERING FACULTY OF CIVIL & ENVIRONMENTAL ENGINEERING UNIVERSITI TUN HUSSEIN ONN MALAYSIA BATU PAHAT, JOHOR
“I declare that I have prepared this report with my own efforts. I also declare not receive or give any assistance in preparing this report and make this affirmation in the belief that nothing is in, it is true”
………………………………………. (STUDENT SIGNATURE) NAME : MUHAMMAD HUZAIR BIN ZULKIFLI MATRIC NO. : DF100040 DATE : 11 DECEMBER 2011
1.0
INTRODUCTION Pumps can
be
arranged
in
serial
or parallel
to provide
additional
head or flow rate capacity. i) Pumps in Serial - Heads Added When two (or more) pumps are arranged in serial, their resulting pump performance curve is obtained by adding their heads at same flow rate as indicated in the figure below.
Figure 1 - Pumps in Serial - Heads Added Centrifugal pump in series are used to overcome larger system head loss than one pump can handle alone. For two identical pumps in series the head will be twice the head of a single pump at the same flow rate. With constant flowrates the combined head moves from 1 to 2. In practice the combined head and flow rated moved along the system curve to 3. If one of the pumps stops, the operation point moves along the system resistance curve from point 1 to point 2 - head and flow rate are decreased. Series operation of single stage pumps is seldom encountered - more often multistage centrifugal pumps are used. ii) Pumps in Parallel - Flow Rate Added When two or more pumps are arranged in parallel their resulting performance curve is obtained by adding their flowrates at the same head as indicated in the figure below.
Figure 2 - Pumps in Parallel - Flow Rate Added Centrifugal pumps in parallel are used to overcome larger volume flows than one pump can handle alone. For two identical pumps in parallel the flowrate will double (moving from 1 to 2) compared to a single pump if head is kept constant. In practice the combined head and volume flow moves along the system curve as indicated from 1 to 3. If one of the pumps in parallel or series stops, the operation point moves along the system resistance curve from point 3 to point 1 the head and flow rate are decreased.
2.0 OBJECTIVE To evaluate the pump characteristics and performance of single two pumps in series and two pumps in parallel at a fixed speed.
3.0
LEARNING OUTCOMES At the end of the course, students should be able to apply the knowledge and skills they have learned to: a. Understand the concept of pump operations b. Understand the pump performances c. Understand the factors which influence the performance of the pump
4.0
THEORY 1. Atmospheric pressure or barometer pressure can be indicated by the absolute pressure minus gauge pressure, Pb = 1013 – 0.1055EL where EL is the elevation above mean seas level at the point to be measured. 2. Pressure head, Hp = P/ (m) where P is the pressure (N/m2) and is the specific weight (kg/m3). 3. Velocity Head, Hv = V2/2g (m) where V is liquid velocity. 4. Static Head, Hs. Height of liquid column above pump centerline on the discharge side of the pump is called Static Discharge Head. Head of liquid column above pump centerline on the pump suction side is called Static Suction Head. If the liquid level on the pump suction side is lower than pump centerline, then height is called Static Suction Lift. Total Static Head is the algebraic difference between Static Discharge Head and Static Suction Head. 5. Friction Head, (Hf) is the small head loss due to friction between liquid and age wall (from the suction side of the pump to the discharge side). The value of loses depend on the flow. The higher the flow rate, the higher is the friction loss. 6. Total Head of Fluid (HT) is the total head at any point of the liquid is the sum of all heads at that particular point, HT = Hp + Hv + HS or HT = P/ + V2/2g + z. 7. Power is the amount of work done per unit time. Power output of pump, Wo = 1.635QP (watts) where Q is flow rate (lt/min) and P is pressure (kg/cm2). Power input to the pump, Wi =1.0277Frn (watts) where F is the dynamometer turning force (watt), r is the dynamometer arm length (m) and n is the prime mover speed (RPM); or Wi = 0.10476Tn (watt) where torque, T = Fr (Nm). 8. Pump efficiency, p = W0/W1 where Wo is the power that pump delivers to liquid and W1 is the input power. 4.1
Centrifugal Pump The principle theory of the centrifugal pump is as follows: 1. Flow rate is directly proportional to the impeller speed and to the third power of the impeller diameter. 2. Total head is directly proportional to the square power of the impeller diameter.
3. Power is directly proportional to the third power of the impeller speed and to the fifth power of the impeller diameter. 4. All the interaction occurs within the pump volute housing creating the Total Dynnamic Head (HTDH). The direction of pump discharge flow is at 90 degree angle to the pump suction flow.
Q1 n1 D13 H 1 n12 D12 p1 n12 D15 5. = ; = ; = where D is impeller diameter, Q Q2 n 2 D23 H 2 n12 D22 p 2 n 23 D25 is flow rate, p is shaft brake horsepower, n is impeller speed, H is total dynamic head, 1 is pump no. 1 and 2 is pump no.2. 6. Typical performance characteristic of centrifugal pump are shown. 4.2
Operational Of Pumps Connected In Series And Parallel Each individual pump has different operating performances characteristics 1. Series Operation In case of two pumps connected for a series operation, the flow rates of pump no. 1 and pump no. 2 will be equal; and the combined Total Head of 2 pump will be equal to the sum of the Total Heads of pump no.1 and no. 2: QT = Q1 + Q2 , Htotal = HT1 + HT2. However in actual practice, the combination Total Head will be slightly lower that HT1 + HT2 due to the additional loss of power in the system as shown in figure (a). 2. Parallel Operation In case of two pumps connected of parallel operation, the pump suction and discharge pressure head will be equal and the combined Total Flow Rate of the system will be the sum of the Flow Rate of Pump no. 1 and pump no. 2, Htotal = HT1 + HT2 and QT = Q1 + Q2 as shown in figure (b).
Figure 3 – Series Operation (a) and Parallel Operation (b)
5.0
EQUIPMENTS This is a self contained bench top unit consisting of two independent sets of centrifugal pump. By manipulating flow control valves, each pump can be operated individually or both pumps connected in series or parallel for measurement of flow rate, head at three different speeds.
Discharge Gauge Water Meter
Valve
Suction Gauge
Pump Main Power Figure 4 – Series and Parallel Pump Equipment
Figure 5 – Stopwatch
6.0
PROCEDURES 1. Hydraulics
Bench
storage
tank
fill
water
up
to
a
nearly
full
level
(5-10cm from the top). 2. Make sure that all pressure gauges both in the suction and discharge sides should read “0”. If not, disconnect pressure tube (white plastic tube) at either side to release the pressure and then reconnect it. 3. The schematic piping system of the test set show on a figure below. 4. Turn off both pumps and close the main power of the control board respectively after completion of the test. 5. Record the values of series and parallel.
Figure 6 – Schematic Piping System 6.1
Performance Test of Pump No. 1 1. Close valves V2, V3, and open valves V1, V4 and V5 2. Turn on pump no. 1 and set the speed at high speed 3. Record the following data: i. Suction Pressure =………………kg/cm2 ii. Discharge Pressure =……………kg/cm2 iii. Flow Volume =…………………...liter iv. Time Period =…………………….sec. 4. Slightly close the discharge valve (V5) to further increase the outlet pressure at an increment of 0.1kg/cm2 and repeat 3 5. Repeat 4 until discharge valved is closed 6. Repeat 2 to 5 for medium and low speed levels.
6.2
Performance Test of Pump No. 2 1. Close valves V1, V3, V4, and open valves V2 and V5 2. Turn on pump no. 2 and set the speed at high speed level 3. Record the same data as in 5.1(3) 4. Slightly close the discharge valve (V5) to further increase the outlet pressure at an increment of 0.1kg/cm2 and repeat 3 5. Repeat 4 until discharge valved is closed 6. Repeat 2 to 5 for medium and low speed levels.
6.3
Performance of Pump No. 1 and Pump No. 2 in Series Connection 1. Close valves V2, V4 and open valves V1, V3 and V5 2. Turn on both pumps and set the speed at high speed level 3. Record the following data: i. Suction Pressure, P1 =……...……..kg/cm2 ii. Discharge Pressure, P3 =……….....kg/cm2 iii. Flow Volume =……………………... liter iv. Time Period =………………………..sec. 4. Slightly close the discharge valve (V5) to further increase the outlet pressure at an increment of 0.1kg/cm2 and repeat 3 5. Repeat 4 until discharge valved is closed 6. Repeat 2 to 5 for medium and low speed levels.
6.4
Performance of Pump No. 1 and Pump No. 2 In Parallel Connection 1. Close valves V3 and open valves V1, V2, V4 and V5 2. Turn on both pumps and set the speed at high speed level 3. Record the following data: i. Suction Pressure, P1 and P2 =…….....kg/cm2 ii. Discharge Pressure, P3 =………...…...kg/cm2 iii. Flow Volume =…………………...……..liter iv. Time Period =……………………...…….sec. 4. Slightly close the discharge valve (V5) to further increase the outlet pressure at an increment of 0.1kg/cm2 and repeat 3 5. Repeat 4 until discharge valved is closed 6. Repeat 2 to 5 for medium and low speed levels.
7.0
RESULT
a) Pump No.1 SPEED 2 PDIS
PSUC 2
Time 2
Flowrate,
SPEED 3 PTOTAL 2
PHEAD 2
PDIS
PSUC 2
Time 2
Flowrate,
PTOTAL 2
PHEAD
(kg/cm )
(kg/cm )
(s/30ltr)
Q (ltr/min)
(kg/m )
(kg/m )
(kg/cm )
(kg/cm )
(s/30ltr)
Q (ltr/min)
(kg/m )
(kg/m2)
0.15
0.08
21.28”
84.568
0.007
0.069
0.08
0.30
24.36”
73.89
0.022
0.216
0.25
0.08
25.31”
71.118
0.017
0.167
0.16
0.30
29.44”
61.14
0.006
0.137
0.35
0.08
32.91”
54.695
0.027
0.265
0.26
0.28
39.28”
45.28
0.002
0.020
0.45
0.08
49.31”
36.504
0.037
0.363
0.34
0.28
86.06”
20.92
0.006
0.059
0.54
0.08
70.13”
25.667
0.046
0.451
0.42
0.28
141.04”
12.76
0.014
0.137
PTOTAL
PHEAD
b) Pump No.2 SPEED 2 PDIS
PSUC 2
Time 2
Flowrate,
SPEED 3 PTOTAL 2
PHEAD 2
PDIS
PSUC 2
Time 2
Flowrate,
2
(kg/cm )
(kg/cm )
(s/30ltr)
Q (ltr/min)
(kg/m )
(kg/m )
(kg/cm )
(kg/cm )
(s/30ltr)
Q (ltr/min)
(kg/m )
(kg/m2)
0.26
0.22
64.19”
28.042
0.004
0.039
0.12
0.34
28.44”
63.29
0.022
0.216
0.27
0.22
64.19”
28.042
0.005
0.049
0.16
0.34
30.37”
59.27
0.018
0.177
0.28
0.22
99.71”
18.052
0.006
0.059
0.22
0.32
33.78”
53.29
0.010
0.098
0.29
0.22
99.71”
18.052
0.007
0.069
0.26
0.32
37.22”
48.36
0.006
0.059
0.30
0.22
179.29”
10.040
0.008
0.078
0.30
0.32
40.00”
45.00
0.002
0.020
c) Pump No. 1 and No.2 in Series Operation SPEED 2 PDIS
PSUC 2
Time 2
Flowrate,
SPEED 3 PTOTAL 2
PHEAD 2
PDIS
PSUC 2
Time 2
Flowrate,
PTOTAL 2
PHEAD
(kg/cm )
(kg/cm )
(s/30ltr)
Q (ltr/min)
(kg/m )
(kg/m )
(kg/cm )
(kg/cm )
(s/30ltr)
Q (ltr/min)
(kg/m )
(kg/m2)
0.04
0.32
24.44”
73.65
0.028
0.275
0.10
0.42
16.90”
106.51
0.032
0.314
0.31
0.26
31.31”
57.49
0.005
0.049
0.34
0.38
22.09”
81.48
0.004
0.034
0.57
0.26
40.60”
44.33
0.031
0.304
0.58
0.38
29.34”
61.35
0.020
0.196
0.84
0.26
55.78”
32.27
0.058
0.569
0.82
0.34
43.66”
41.23
0.048
0.471
1.10
0.26
66.09”
27.24
0.084
0.824
1.06
0.34
124.68”
14.44
0.072
0.706
d) Pump No. 1 and No.2 in Parallel Operation SPEED 2
SPEED 3
PDIS
PSUC
Time
Flowrate,
PTOTAL
PHEAD
PDIS
PSUC
Time
Flowrate,
PTOTAL
PHEAD
(kg/cm2)
(kg/cm2)
(s/30ltr)
Q (ltr/min)
(kg/m2)
(kg/m2)
(kg/cm2)
(kg/cm2)
(s/30ltr)
Q (ltr/min)
(kg/m2)
(kg/m2)
0.04
0.49
22.78”
79.02
0.045
0.441
0.04
0.53
18.87”
95.39
0.049
0.481
0.19
0.49
36.32”
49.56
0.030
0.294
0.16
0.52
23.65”
76.11
0.036
0.353
0.33
0.49
57.94”
31.07
0.016
0.157
0.30
0.52
26.50”
67.92
0.022
0.216
0.48
0.49
88.78”
20.27
0.001
0.010
0.42
0.51
35.03”
51.38
0.009
0.088
0.62
0.49
190.41”
9.45
0.013
0.128
0.54
0.50
56.22”
32.12
0.004
0.039
8.0
ANALYSIS DATA Calculation for Flowrate,Q (Ltr/min), PTOTAL (kg/m2) and PHEAD (kg/m2) a) Calculation for Speed 3, Pump No.1 PDIS 0.08
0.16
0.26
0.34
0.42
Flowrate,Q (ltr/min) = 30 lt x 60s time,s 1 min = 30 lt x 60s 24.36s 1 min = 73.89 lt/min = 30 lt x 60s 29.44s 1 min = 61.14 lt/min = 30 lt x 60s 39.28s 1 min = 45.28 lt/min = 30 lt x 60s 86.06s 1 min = 20.92 lt/min = 30 lt x 60s 141.04s 1 min = 12.76 lt/min
PTOTAL (kg/m2) = (PDIS – PSUC) x 1000 1002 = (0.08 – 0.30) x 1000 1002 2
= 0.022 kg/m = (0.16 – 0.30) x 1000 1002 2
= 0.014 kg/m = (0.26 – 0.28) x 1000 1002 2
= 0.002 kg/m = (0.34 – 0.28) x 1000 1002 2
= 0.006 kg/m = (0.42 – 0.28) x 1000 1002 2
= 0.014 kg/m
PHEAD (kg/m2) = (PTOTAL x 9.81) = 0.022 x 9.81 = 0.216 kg/m2 = 0.014 x 9.81 = 0.137 kg/m2 = 0.002 x 9.81 = 0.020 kg/m2 = 0.006 x 9.81 = 0.059 kg/m2 = 0.014 x 9.81 = 0.137 kg/m2
b) Calculation for Speed 3, Pump No.2 PDIS 0.08
0.16
0.26
0.34
0.42
Flowrate,Q (ltr/min) = 30 lt x 60s time,s 1 min = 30 lt x 60s 28.44s 1 min
PTOTAL (kg/m2) = (PDIS – PSUC) x 1000 1002 = (0.12 – 0.34) x 1000 1002
= 63.29 lt/min = 30 lt x 60s 30.37s 1 min
= 0.022 kg/m2 = (0.16 – 0.34) x 1000 1002
= 59.27 lt/min = 30 lt x 60s 33.78s 1 min
= 0.018 kg/m2 = (0.22 – 0.32) x 1000 1002
= 53.29 lt/min = 30 lt x 60s 37.22s 1 min
= 0.010 kg/m2 = (0.26 – 0.32) x 1000 1002
= 48.36 lt/min = 30 lt x 60s 40.00s 1 min
= 0.006 kg/m2 = (0.30 – 0.32) x 1000 1002
= 45.00 lt/min
= 0.002 kg/m2
PHEAD (kg/m2) = (PTOTAL x 9.81) = 0.022 x 9.81 = 0.216 kg/m2 = 0.018 x 9.81 = 0.177 kg/m2 = 0.010 x 9.81 = 0.098 kg/m2 = 0.006 x 9.81 = 0.059 kg/m2 = 0.002 x 9.81 = 0.020 kg/m2
c) Calculation for Series Operation, Pump No.1 and No.2 PDIS 0.08
0.16
0.26
0.34
0.42
Flowrate,Q (ltr/min) = 30 lt x 60s time,s 1 min = 30 lt x 60s 16.90s 1 min
PTOTAL (kg/m2) = (PDIS – PSUC) x 1000 1002 = (0.10 – 0.42) x 1000 1002
= 106.51 lt/min = 30 lt x 60s 22.09s 1 min
= 0.032 kg/m2 = (0.34 – 0.38) x 1000 1002
= 81.48 lt/min = 30 lt x 60s 29.34s 1 min
= 0.004 kg/m2 = (0.58 – 0.38) x 1000 1002
= 61.35 lt/min = 30 lt x 60s 43.66s 1 min
= 0.020 kg/m2 = (0.82 – 0.34) x 1000 1002
= 41.23 lt/min = 30 lt x 60s 124.68s 1 min
= 0.048 kg/m2 = (1.06 – 0.34) x 1000 1002
= 14.44 lt/min
= 0.072 kg/m2
PHEAD (kg/m2) = (PTOTAL x 9.81) = -0.032 x 9.81 = 0.314 kg/m2 = 0.004 x 9.81 = 0.039 kg/m2 = 0.020 x 9.81 = 0.196 kg/m2 = 0.048 x 9.81 = 0.471 kg/m2 = 0.072 x 9.81 = 0.706 kg/m2
d) Calculation for Parallel Operation, Pump No.1 and No.2 PDIS 0.08
0.16
0.26
0.34
0.42
Flowrate,Q (ltr/min) = 30 lt x 60s time,s 1 min = 30 lt x 60s 18.87s 1 min
PTOTAL (kg/m2) = (PDIS – PSUC) x 1000 1002 = (0.04 – 0.53) x 1000 1002
= 95.39 lt/min = 30 lt x 60s 23.65s 1 min
= 0.049 kg/m2 = (0.16 – 0.52) x 1000 1002
= 76.11 lt/min = 30 lt x 60s 26.50s 1 min
= 0.036 kg/m2 = (0.30 – 0.52) x 1000 1002
= 67.92 lt/min = 30 lt x 60s 35.03s 1 min
= 0.022 kg/m2 = (0.42 – 0.51) x 1000 1002
= 51.38 lt/min = 30 lt x 60s 56.22s 1 min
= 0.009 kg/m2 = (0.54 – 0.50) x 1000 1002
= 32.12 lt/min
= 0.004 kg/m2
PHEAD (kg/m2) = (PTOTAL x 9.81) = 0.049 x 9.81 = 0.481 kg/m2 = 0.036 x 9.81 = 0.353 kg/m2 = 0.022 x 9.81 = 0.216 kg/m2 = 0.009 x 9.81 = 0.088 kg/m2 = 0.004 x 9.81 = 0.039 kg/m2
9.0
QUESTIONS
1. For pump no.1 and no.2 : Plot curve showing flowrate on the Y-axis versus pressure (occasionally expressed in metres of head) on the X-axis for a constant pump speed by drawing smooth curve through points obtained from the calculations. Graph flowrate versus pressure (speed 2) Based on the graph, we show that the pressures are decrease when the flowrate are increase. Compare between pump no. 1 and pump no. 2, the curve of pump 1 are higher than pump 2. Graph flowrate versus pressure (speed 3) Based on the graph, the speed 3 is faster than speed 2, so, it has more flowrate with less value of pressure head. Compare between pump no. 1 and pump no. 2, the curve of pump 1 are higher than pump 2. 2. For both two pumps in series and parallel operation : In this case of series and parallel operation, please compare the additional pressure and flowrate according to the theory. Graph flowrate versus pressure-series and parallel (speed 2) From the graph, we show that have different curve between series and parallel operation. The curve of parallel operation is higher than the curve of series operation. The value flowrate of parallel are more than flowrate of series operation. Graph flowrate versus pressure-series and parallel (speed 3) From the graph, there is also difference in curve between series and parallel operation. The curve of parallel operation is lower than the curve of series operation. The value flowrate of parallel are less than flowrate of series operation.
10.0 DISCUSSION A pump is a device used to move liquids, or slurries. A pump moves liquids from lower pressure to higher pressure, and overcomes this difference in pressure by adding energy to the system (such as a water system). A gas pump is generally called a compressor, except in very low pressure-rise applications, such as in heating, ventilating, and air-conditioning, the equipment is known as fans or blowers. Based on the result from the table, the increment of flow rate was influence to the decreasing of pressure head of suction that give a negative sign. These two data was influence to the pressure in discharge section which is controlled. So, i.
Manipulated variable shows by the pressure in discharge and speed of pump.
ii.
Dependent variable shows by the pressure in suction and flow rate.
iii.
Constant variable shows by the volume of water in the tank.
Discharge Cavitations Discharge Cavitations occurs when the pump discharge is extremely high. It normally occurs in a pump that is running at less than 10% of its best efficiency point. The high discharge pressure causes the majority of the fluid to circulate inside the pump instead of being allowed to flow out the discharge. As the liquid flows around the impeller it must through the small clearance between the impeller and the pump cutwater at extremely high velocity. This velocity causes a vacuum to develop at the cutwater similar to what occurs in a venture and turns the liquid into a vapor. A pump that has been operating under these conditions shows premature wear of the impeller vane tips and the pump cutwater. Suction Cavitations Suction Cavitations occurs when the pump suction is under a low pressure/high vacuum condition where the liquid turns into a vapor at the eye of the pump impeller. This vapor is carried over to the discharge side of the pump where it no longer sees vacuum and is compressed back into a liquid by the discharge pressure. This imploding action occurs violently and attacks the face of the impeller. An impeller that has been operating under a suction cavitations condition has large chunks of material removed from its face causing premature failure of the pump.
Figure 7 – High Discharge Pressure
Figure 8 – Low Pressure
From the table and graph, overall we can say that flow rate increase when the pressure head in suction decrease to negative value. This sign shows that there are vacuum conditions at the point after we placed the pump that allowing water to suck in that point to make the water move in the pipe. This sign also tell that the point is in low pressure than other point in the tank and before we placed the pump. So, the higher pressure will be suck to the lower pressure because it is a concept of pressure. This experiment didn’t give an exact value cause by some errors in the system and other factors, such as:
Parallax error.
It happens while taking a reading using gauge meter and stop watch where the reader didn’t use a proper way to get a right reading.
To prevent this problem, the reader should learn and practise by understand the procedure to get reading otherwise get some help. Other than that, the reader should have sharp eye because meter gauge don’t give a small scale to use. He or she must estimate the value correctly or nearly for right value that can be used.
Systematic error.
This error cause by apparatus that are not perfect and have some problem such as leaking or a big losses energy cause by friction in the pipe.
To prevent this error, the apparatus should be test before the experiment begins. Random error.
There are many data that was taken and sometimes the data didn’t give a good results cause by randomly results. To reduce this, reader should take more than one reading and take the average. Additionally, a person who takes the reading should not be changed.
11.0 CONCLUSION According to the experiments, can evaluate the pump characteristics and performances of single two pumps in series and two pumps in parallel at a fixed speed. Pumps are used to convert mechanical energy into fluid energy and allow liquids to be moved from one place to another. From this experiment, can understand fully the types of pumps available and their different characteristics. Measurements of head, flow, speed and torque allow the performance of each pump to be determined and compared. Therefore, the experiments assumed success.
12.0 REFERENCES
Roberson, J.A, Cassidy, J.J & Chaudry, M.H. (1998) ‘Hydraulic Engineering’, Wiley.
Ab Aziz Abdul Latiff, Hidraulik, Jabatan Kejuruteraan Awam Dan Alam Sekitar, Penerbit UTHM.
White Frank M.(1979). Fluid Mechanics. Mc Graw, Hill.University of Rhode Island. United States of America, pg 636 - 642.
LAB REPORT Subject Code Code & Experiment Title Course Code Date Section / Group Name of Group Lecturer/Instructor/Tutor Received Date
Comment by examiner
BFC 21201 MKA – 04 ; SERIES AND PARALLEL PUMP TEST 2 BFF/1 5 DECEMBER 2011 5/2 MUHAMMAD IKHWAN BIN ZAINUDDIN (DF100018) 1. AFANDI BIN ABD WAHID (DF100122) 2.MOHD HASIF BIN AZMAN (DF100079) 3.MUHAMMAD HUZAIR BIN ZULKIFLI (DF100040) CIK AMNANI BIN ABU BAKAR EN JAMILULLAIL BIN AHMAD TAIB 12 DECEMBER 2011
Received
STUDENTS’ ETHICAL CODE (SEC) DEPARTMENT OF WATER & ENVIRONMENTAL ENGINEERING FACULTY OF CIVIL & ENVIRONMENTAL ENGINEERING UNIVERSITI TUN HUSSEIN ONN MALAYSIA BATU PAHAT, JOHOR
“I declare that I have prepared this report with my own efforts. I also declare not receive or give any assistance in preparing this report and make this affirmation in the belief that nothing is in, it is true”
………………………………………. (STUDENT SIGNATURE) NAME : MUHAMMAD IKHWAN BIN ZAINUDDIN MATRIC NO. : DF100018 DATE : 11 DECEMBER 2011
STUDENTS’ ETHICAL CODE (SEC) DEPARTMENT OF WATER & ENVIRONMENTAL ENGINEERING FACULTY OF CIVIL & ENVIRONMENTAL ENGINEERING UNIVERSITI TUN HUSSEIN ONN MALAYSIA BATU PAHAT, JOHOR
“I declare that I have prepared this report with my own efforts. I also declare not receive or give any assistance in preparing this report and make this affirmation in the belief that nothing is in, it is true”
………………………………………. (STUDENT SIGNATURE) NAME : AFANDI BIN ABD WAHID MATRIC NO. : DF100122 DATE : 11 DECEMBER 2011
STUDENTS’ ETHICAL CODE (SEC) DEPARTMENT OF WATER & ENVIRONMENTAL ENGINEERING FACULTY OF CIVIL & ENVIRONMENTAL ENGINEERING UNIVERSITI TUN HUSSEIN ONN MALAYSIA BATU PAHAT, JOHOR
“I declare that I have prepared this report with my own efforts. I also declare not receive or give any assistance in preparing this report and make this affirmation in the belief that nothing is in, it is true”
………………………………………. (STUDENT SIGNATURE) NAME : MOHD HASIF BIN AZMAN MATRIC NO. : DF100079 DATE : 11 DECEMBER 2011
STUDENTS’ ETHICAL CODE (SEC) DEPARTMENT OF WATER & ENVIRONMENTAL ENGINEERING FACULTY OF CIVIL & ENVIRONMENTAL ENGINEERING UNIVERSITI TUN HUSSEIN ONN MALAYSIA BATU PAHAT, JOHOR
“I declare that I have prepared this report with my own efforts. I also declare not receive or give any assistance in preparing this report and make this affirmation in the belief that nothing is in, it is true”
………………………………………. (STUDENT SIGNATURE) NAME : MUHAMMAD HUZAIR BIN ZULKIFLI MATRIC NO. : DF100040 DATE : 11 DECEMBER 2011
1.0
INTRODUCTION Pumps can
be
arranged
in
serial
or parallel
to provide
additional
head or flow rate capacity. i) Pumps in Serial - Heads Added When two (or more) pumps are arranged in serial, their resulting pump performance curve is obtained by adding their heads at same flow rate as indicated in the figure below.
Figure 1 - Pumps in Serial - Heads Added Centrifugal pump in series are used to overcome larger system head loss than one pump can handle alone. For two identical pumps in series the head will be twice the head of a single pump at the same flow rate. With constant flowrates the combined head moves from 1 to 2. In practice the combined head and flow rated moved along the system curve to 3. If one of the pumps stops, the operation point moves along the system resistance curve from point 1 to point 2 - head and flow rate are decreased. Series operation of single stage pumps is seldom encountered - more often multistage centrifugal pumps are used. ii) Pumps in Parallel - Flow Rate Added When two or more pumps are arranged in parallel their resulting performance curve is obtained by adding their flowrates at the same head as indicated in the figure below.
Figure 2 - Pumps in Parallel - Flow Rate Added Centrifugal pumps in parallel are used to overcome larger volume flows than one pump can handle alone. For two identical pumps in parallel the flowrate will double (moving from 1 to 2) compared to a single pump if head is kept constant. In practice the combined head and volume flow moves along the system curve as indicated from 1 to 3. If one of the pumps in parallel or series stops, the operation point moves along the system resistance curve from point 3 to point 1 the head and flow rate are decreased.
2.0 OBJECTIVE To evaluate the pump characteristics and performance of single two pumps in series and two pumps in parallel at a fixed speed.
3.0
LEARNING OUTCOMES At the end of the course, students should be able to apply the knowledge and skills they have learned to: a. Understand the concept of pump operations b. Understand the pump performances c. Understand the factors which influence the performance of the pump
4.0
THEORY 1. Atmospheric pressure or barometer pressure can be indicated by the absolute pressure minus gauge pressure, Pb = 1013 – 0.1055EL where EL is the elevation above mean seas level at the point to be measured. 2. Pressure head, Hp = P/ (m) where P is the pressure (N/m2) and is the specific weight (kg/m3). 3. Velocity Head, Hv = V2/2g (m) where V is liquid velocity. 4. Static Head, Hs. Height of liquid column above pump centerline on the discharge side of the pump is called Static Discharge Head. Head of liquid column above pump centerline on the pump suction side is called Static Suction Head. If the liquid level on the pump suction side is lower than pump centerline, then height is called Static Suction Lift. Total Static Head is the algebraic difference between Static Discharge Head and Static Suction Head. 5. Friction Head, (Hf) is the small head loss due to friction between liquid and age wall (from the suction side of the pump to the discharge side). The value of loses depend on the flow. The higher the flow rate, the higher is the friction loss. 6. Total Head of Fluid (HT) is the total head at any point of the liquid is the sum of all heads at that particular point, HT = Hp + Hv + HS or HT = P/ + V2/2g + z. 7. Power is the amount of work done per unit time. Power output of pump, Wo = 1.635QP (watts) where Q is flow rate (lt/min) and P is pressure (kg/cm2). Power input to the pump, Wi =1.0277Frn (watts) where F is the dynamometer turning force (watt), r is the dynamometer arm length (m) and n is the prime mover speed (RPM); or Wi = 0.10476Tn (watt) where torque, T = Fr (Nm). 8. Pump efficiency, p = W0/W1 where Wo is the power that pump delivers to liquid and W1 is the input power. 4.1
Centrifugal Pump The principle theory of the centrifugal pump is as follows: 1. Flow rate is directly proportional to the impeller speed and to the third power of the impeller diameter. 2. Total head is directly proportional to the square power of the impeller diameter.
3. Power is directly proportional to the third power of the impeller speed and to the fifth power of the impeller diameter. 4. All the interaction occurs within the pump volute housing creating the Total Dynnamic Head (HTDH). The direction of pump discharge flow is at 90 degree angle to the pump suction flow.
Q1 n1 D13 H 1 n12 D12 p1 n12 D15 5. = ; = ; = where D is impeller diameter, Q Q2 n 2 D23 H 2 n12 D22 p 2 n 23 D25 is flow rate, p is shaft brake horsepower, n is impeller speed, H is total dynamic head, 1 is pump no. 1 and 2 is pump no.2. 6. Typical performance characteristic of centrifugal pump are shown. 4.2
Operational Of Pumps Connected In Series And Parallel Each individual pump has different operating performances characteristics 1. Series Operation In case of two pumps connected for a series operation, the flow rates of pump no. 1 and pump no. 2 will be equal; and the combined Total Head of 2 pump will be equal to the sum of the Total Heads of pump no.1 and no. 2: QT = Q1 + Q2 , Htotal = HT1 + HT2. However in actual practice, the combination Total Head will be slightly lower that HT1 + HT2 due to the additional loss of power in the system as shown in figure (a). 2. Parallel Operation In case of two pumps connected of parallel operation, the pump suction and discharge pressure head will be equal and the combined Total Flow Rate of the system will be the sum of the Flow Rate of Pump no. 1 and pump no. 2, Htotal = HT1 + HT2 and QT = Q1 + Q2 as shown in figure (b).
Figure 3 – Series Operation (a) and Parallel Operation (b)
5.0
EQUIPMENTS This is a self contained bench top unit consisting of two independent sets of centrifugal pump. By manipulating flow control valves, each pump can be operated individually or both pumps connected in series or parallel for measurement of flow rate, head at three different speeds.
Discharge Gauge Water Meter
Valve
Suction Gauge
Pump Main Power Figure 4 – Series and Parallel Pump Equipment
Figure 5 – Stopwatch
6.0
PROCEDURES 1. Hydraulics
Bench
storage
tank
fill
water
up
to
a
nearly
full
level
(5-10cm from the top). 2. Make sure that all pressure gauges both in the suction and discharge sides should read “0”. If not, disconnect pressure tube (white plastic tube) at either side to release the pressure and then reconnect it. 3. The schematic piping system of the test set show on a figure below. 4. Turn off both pumps and close the main power of the control board respectively after completion of the test. 5. Record the values of series and parallel.
Figure 6 – Schematic Piping System 6.1
Performance Test of Pump No. 1 1. Close valves V2, V3, and open valves V1, V4 and V5 2. Turn on pump no. 1 and set the speed at high speed 3. Record the following data: i. Suction Pressure =………………kg/cm2 ii. Discharge Pressure =……………kg/cm2 iii. Flow Volume =…………………...liter iv. Time Period =…………………….sec. 4. Slightly close the discharge valve (V5) to further increase the outlet pressure at an increment of 0.1kg/cm2 and repeat 3 5. Repeat 4 until discharge valved is closed 6. Repeat 2 to 5 for medium and low speed levels.
6.2
Performance Test of Pump No. 2 1. Close valves V1, V3, V4, and open valves V2 and V5 2. Turn on pump no. 2 and set the speed at high speed level 3. Record the same data as in 5.1(3) 4. Slightly close the discharge valve (V5) to further increase the outlet pressure at an increment of 0.1kg/cm2 and repeat 3 5. Repeat 4 until discharge valved is closed 6. Repeat 2 to 5 for medium and low speed levels.
6.3
Performance of Pump No. 1 and Pump No. 2 in Series Connection 1. Close valves V2, V4 and open valves V1, V3 and V5 2. Turn on both pumps and set the speed at high speed level 3. Record the following data: i. Suction Pressure, P1 =……...……..kg/cm2 ii. Discharge Pressure, P3 =……….....kg/cm2 iii. Flow Volume =……………………... liter iv. Time Period =………………………..sec. 4. Slightly close the discharge valve (V5) to further increase the outlet pressure at an increment of 0.1kg/cm2 and repeat 3 5. Repeat 4 until discharge valved is closed 6. Repeat 2 to 5 for medium and low speed levels.
6.4
Performance of Pump No. 1 and Pump No. 2 In Parallel Connection 1. Close valves V3 and open valves V1, V2, V4 and V5 2. Turn on both pumps and set the speed at high speed level 3. Record the following data: i. Suction Pressure, P1 and P2 =…….....kg/cm2 ii. Discharge Pressure, P3 =………...…...kg/cm2 iii. Flow Volume =…………………...……..liter iv. Time Period =……………………...…….sec. 4. Slightly close the discharge valve (V5) to further increase the outlet pressure at an increment of 0.1kg/cm2 and repeat 3 5. Repeat 4 until discharge valved is closed 6. Repeat 2 to 5 for medium and low speed levels.
7.0
RESULT
a) Pump No.1 SPEED 2 PDIS
PSUC 2
Time 2
Flowrate,
SPEED 3 PTOTAL 2
PHEAD 2
PDIS
PSUC 2
Time 2
Flowrate,
PTOTAL 2
PHEAD
(kg/cm )
(kg/cm )
(s/30ltr)
Q (ltr/min)
(kg/m )
(kg/m )
(kg/cm )
(kg/cm )
(s/30ltr)
Q (ltr/min)
(kg/m )
(kg/m2)
0.15
0.08
21.28”
84.568
0.007
0.069
0.08
0.30
24.36”
73.89
0.022
0.216
0.25
0.08
25.31”
71.118
0.017
0.167
0.16
0.30
29.44”
61.14
0.006
0.137
0.35
0.08
32.91”
54.695
0.027
0.265
0.26
0.28
39.28”
45.28
0.002
0.020
0.45
0.08
49.31”
36.504
0.037
0.363
0.34
0.28
86.06”
20.92
0.006
0.059
0.54
0.08
70.13”
25.667
0.046
0.451
0.42
0.28
141.04”
12.76
0.014
0.137
PTOTAL
PHEAD
b) Pump No.2 SPEED 2 PDIS
PSUC 2
Time 2
Flowrate,
SPEED 3 PTOTAL 2
PHEAD 2
PDIS
PSUC 2
Time 2
Flowrate,
2
(kg/cm )
(kg/cm )
(s/30ltr)
Q (ltr/min)
(kg/m )
(kg/m )
(kg/cm )
(kg/cm )
(s/30ltr)
Q (ltr/min)
(kg/m )
(kg/m2)
0.26
0.22
64.19”
28.042
0.004
0.039
0.12
0.34
28.44”
63.29
0.022
0.216
0.27
0.22
64.19”
28.042
0.005
0.049
0.16
0.34
30.37”
59.27
0.018
0.177
0.28
0.22
99.71”
18.052
0.006
0.059
0.22
0.32
33.78”
53.29
0.010
0.098
0.29
0.22
99.71”
18.052
0.007
0.069
0.26
0.32
37.22”
48.36
0.006
0.059
0.30
0.22
179.29”
10.040
0.008
0.078
0.30
0.32
40.00”
45.00
0.002
0.020
c) Pump No. 1 and No.2 in Series Operation SPEED 2 PDIS
PSUC 2
Time 2
Flowrate,
SPEED 3 PTOTAL 2
PHEAD 2
PDIS
PSUC 2
Time 2
Flowrate,
PTOTAL 2
PHEAD
(kg/cm )
(kg/cm )
(s/30ltr)
Q (ltr/min)
(kg/m )
(kg/m )
(kg/cm )
(kg/cm )
(s/30ltr)
Q (ltr/min)
(kg/m )
(kg/m2)
0.04
0.32
24.44”
73.65
0.028
0.275
0.10
0.42
16.90”
106.51
0.032
0.314
0.31
0.26
31.31”
57.49
0.005
0.049
0.34
0.38
22.09”
81.48
0.004
0.034
0.57
0.26
40.60”
44.33
0.031
0.304
0.58
0.38
29.34”
61.35
0.020
0.196
0.84
0.26
55.78”
32.27
0.058
0.569
0.82
0.34
43.66”
41.23
0.048
0.471
1.10
0.26
66.09”
27.24
0.084
0.824
1.06
0.34
124.68”
14.44
0.072
0.706
d) Pump No. 1 and No.2 in Parallel Operation SPEED 2
SPEED 3
PDIS
PSUC
Time
Flowrate,
PTOTAL
PHEAD
PDIS
PSUC
Time
Flowrate,
PTOTAL
PHEAD
(kg/cm2)
(kg/cm2)
(s/30ltr)
Q (ltr/min)
(kg/m2)
(kg/m2)
(kg/cm2)
(kg/cm2)
(s/30ltr)
Q (ltr/min)
(kg/m2)
(kg/m2)
0.04
0.49
22.78”
79.02
0.045
0.441
0.04
0.53
18.87”
95.39
0.049
0.481
0.19
0.49
36.32”
49.56
0.030
0.294
0.16
0.52
23.65”
76.11
0.036
0.353
0.33
0.49
57.94”
31.07
0.016
0.157
0.30
0.52
26.50”
67.92
0.022
0.216
0.48
0.49
88.78”
20.27
0.001
0.010
0.42
0.51
35.03”
51.38
0.009
0.088
0.62
0.49
190.41”
9.45
0.013
0.128
0.54
0.50
56.22”
32.12
0.004
0.039
8.0
ANALYSIS DATA Calculation for Flowrate,Q (Ltr/min), PTOTAL (kg/m2) and PHEAD (kg/m2) a) Calculation for Speed 3, Pump No.1 PDIS 0.08
0.16
0.26
0.34
0.42
Flowrate,Q (ltr/min) = 30 lt x 60s time,s 1 min = 30 lt x 60s 24.36s 1 min = 73.89 lt/min = 30 lt x 60s 29.44s 1 min = 61.14 lt/min = 30 lt x 60s 39.28s 1 min = 45.28 lt/min = 30 lt x 60s 86.06s 1 min = 20.92 lt/min = 30 lt x 60s 141.04s 1 min = 12.76 lt/min
PTOTAL (kg/m2) = (PDIS – PSUC) x 1000 1002 = (0.08 – 0.30) x 1000 1002 2
= 0.022 kg/m = (0.16 – 0.30) x 1000 1002 2
= 0.014 kg/m = (0.26 – 0.28) x 1000 1002 2
= 0.002 kg/m = (0.34 – 0.28) x 1000 1002 2
= 0.006 kg/m = (0.42 – 0.28) x 1000 1002 2
= 0.014 kg/m
PHEAD (kg/m2) = (PTOTAL x 9.81) = 0.022 x 9.81 = 0.216 kg/m2 = 0.014 x 9.81 = 0.137 kg/m2 = 0.002 x 9.81 = 0.020 kg/m2 = 0.006 x 9.81 = 0.059 kg/m2 = 0.014 x 9.81 = 0.137 kg/m2
b) Calculation for Speed 3, Pump No.2 PDIS 0.08
0.16
0.26
0.34
0.42
Flowrate,Q (ltr/min) = 30 lt x 60s time,s 1 min = 30 lt x 60s 28.44s 1 min
PTOTAL (kg/m2) = (PDIS – PSUC) x 1000 1002 = (0.12 – 0.34) x 1000 1002
= 63.29 lt/min = 30 lt x 60s 30.37s 1 min
= 0.022 kg/m2 = (0.16 – 0.34) x 1000 1002
= 59.27 lt/min = 30 lt x 60s 33.78s 1 min
= 0.018 kg/m2 = (0.22 – 0.32) x 1000 1002
= 53.29 lt/min = 30 lt x 60s 37.22s 1 min
= 0.010 kg/m2 = (0.26 – 0.32) x 1000 1002
= 48.36 lt/min = 30 lt x 60s 40.00s 1 min
= 0.006 kg/m2 = (0.30 – 0.32) x 1000 1002
= 45.00 lt/min
= 0.002 kg/m2
PHEAD (kg/m2) = (PTOTAL x 9.81) = 0.022 x 9.81 = 0.216 kg/m2 = 0.018 x 9.81 = 0.177 kg/m2 = 0.010 x 9.81 = 0.098 kg/m2 = 0.006 x 9.81 = 0.059 kg/m2 = 0.002 x 9.81 = 0.020 kg/m2
c) Calculation for Series Operation, Pump No.1 and No.2 PDIS 0.08
0.16
0.26
0.34
0.42
Flowrate,Q (ltr/min) = 30 lt x 60s time,s 1 min = 30 lt x 60s 16.90s 1 min
PTOTAL (kg/m2) = (PDIS – PSUC) x 1000 1002 = (0.10 – 0.42) x 1000 1002
= 106.51 lt/min = 30 lt x 60s 22.09s 1 min
= 0.032 kg/m2 = (0.34 – 0.38) x 1000 1002
= 81.48 lt/min = 30 lt x 60s 29.34s 1 min
= 0.004 kg/m2 = (0.58 – 0.38) x 1000 1002
= 61.35 lt/min = 30 lt x 60s 43.66s 1 min
= 0.020 kg/m2 = (0.82 – 0.34) x 1000 1002
= 41.23 lt/min = 30 lt x 60s 124.68s 1 min
= 0.048 kg/m2 = (1.06 – 0.34) x 1000 1002
= 14.44 lt/min
= 0.072 kg/m2
PHEAD (kg/m2) = (PTOTAL x 9.81) = -0.032 x 9.81 = 0.314 kg/m2 = 0.004 x 9.81 = 0.039 kg/m2 = 0.020 x 9.81 = 0.196 kg/m2 = 0.048 x 9.81 = 0.471 kg/m2 = 0.072 x 9.81 = 0.706 kg/m2
d) Calculation for Parallel Operation, Pump No.1 and No.2 PDIS 0.08
0.16
0.26
0.34
0.42
Flowrate,Q (ltr/min) = 30 lt x 60s time,s 1 min = 30 lt x 60s 18.87s 1 min
PTOTAL (kg/m2) = (PDIS – PSUC) x 1000 1002 = (0.04 – 0.53) x 1000 1002
= 95.39 lt/min = 30 lt x 60s 23.65s 1 min
= 0.049 kg/m2 = (0.16 – 0.52) x 1000 1002
= 76.11 lt/min = 30 lt x 60s 26.50s 1 min
= 0.036 kg/m2 = (0.30 – 0.52) x 1000 1002
= 67.92 lt/min = 30 lt x 60s 35.03s 1 min
= 0.022 kg/m2 = (0.42 – 0.51) x 1000 1002
= 51.38 lt/min = 30 lt x 60s 56.22s 1 min
= 0.009 kg/m2 = (0.54 – 0.50) x 1000 1002
= 32.12 lt/min
= 0.004 kg/m2
PHEAD (kg/m2) = (PTOTAL x 9.81) = 0.049 x 9.81 = 0.481 kg/m2 = 0.036 x 9.81 = 0.353 kg/m2 = 0.022 x 9.81 = 0.216 kg/m2 = 0.009 x 9.81 = 0.088 kg/m2 = 0.004 x 9.81 = 0.039 kg/m2
9.0
QUESTIONS
1. For pump no.1 and no.2 : Plot curve showing flowrate on the Y-axis versus pressure (occasionally expressed in metres of head) on the X-axis for a constant pump speed by drawing smooth curve through points obtained from the calculations. Graph flowrate versus pressure (speed 2) Based on the graph, we show that the pressures are decrease when the flowrate are increase. Compare between pump no. 1 and pump no. 2, the curve of pump 1 are higher than pump 2. Graph flowrate versus pressure (speed 3) Based on the graph, the speed 3 is faster than speed 2, so, it has more flowrate with less value of pressure head. Compare between pump no. 1 and pump no. 2, the curve of pump 1 are higher than pump 2. 2. For both two pumps in series and parallel operation : In this case of series and parallel operation, please compare the additional pressure and flowrate according to the theory. Graph flowrate versus pressure-series and parallel (speed 2) From the graph, we show that have different curve between series and parallel operation. The curve of parallel operation is higher than the curve of series operation. The value flowrate of parallel are more than flowrate of series operation. Graph flowrate versus pressure-series and parallel (speed 3) From the graph, there is also difference in curve between series and parallel operation. The curve of parallel operation is lower than the curve of series operation. The value flowrate of parallel are less than flowrate of series operation.
10.0 DISCUSSION A pump is a device used to move liquids, or slurries. A pump moves liquids from lower pressure to higher pressure, and overcomes this difference in pressure by adding energy to the system (such as a water system). A gas pump is generally called a compressor, except in very low pressure-rise applications, such as in heating, ventilating, and air-conditioning, the equipment is known as fans or blowers. Based on the result from the table, the increment of flow rate was influence to the decreasing of pressure head of suction that give a negative sign. These two data was influence to the pressure in discharge section which is controlled. So, i.
Manipulated variable shows by the pressure in discharge and speed of pump.
ii.
Dependent variable shows by the pressure in suction and flow rate.
iii.
Constant variable shows by the volume of water in the tank.
Discharge Cavitations Discharge Cavitations occurs when the pump discharge is extremely high. It normally occurs in a pump that is running at less than 10% of its best efficiency point. The high discharge pressure causes the majority of the fluid to circulate inside the pump instead of being allowed to flow out the discharge. As the liquid flows around the impeller it must through the small clearance between the impeller and the pump cutwater at extremely high velocity. This velocity causes a vacuum to develop at the cutwater similar to what occurs in a venture and turns the liquid into a vapor. A pump that has been operating under these conditions shows premature wear of the impeller vane tips and the pump cutwater. Suction Cavitations Suction Cavitations occurs when the pump suction is under a low pressure/high vacuum condition where the liquid turns into a vapor at the eye of the pump impeller. This vapor is carried over to the discharge side of the pump where it no longer sees vacuum and is compressed back into a liquid by the discharge pressure. This imploding action occurs violently and attacks the face of the impeller. An impeller that has been operating under a suction cavitations condition has large chunks of material removed from its face causing premature failure of the pump.
Figure 7 – High Discharge Pressure
Figure 8 – Low Pressure
From the table and graph, overall we can say that flow rate increase when the pressure head in suction decrease to negative value. This sign shows that there are vacuum conditions at the point after we placed the pump that allowing water to suck in that point to make the water move in the pipe. This sign also tell that the point is in low pressure than other point in the tank and before we placed the pump. So, the higher pressure will be suck to the lower pressure because it is a concept of pressure. This experiment didn’t give an exact value cause by some errors in the system and other factors, such as:
Parallax error.
It happens while taking a reading using gauge meter and stop watch where the reader didn’t use a proper way to get a right reading.
To prevent this problem, the reader should learn and practise by understand the procedure to get reading otherwise get some help. Other than that, the reader should have sharp eye because meter gauge don’t give a small scale to use. He or she must estimate the value correctly or nearly for right value that can be used.
Systematic error.
This error cause by apparatus that are not perfect and have some problem such as leaking or a big losses energy cause by friction in the pipe.
To prevent this error, the apparatus should be test before the experiment begins. Random error.
There are many data that was taken and sometimes the data didn’t give a good results cause by randomly results. To reduce this, reader should take more than one reading and take the average. Additionally, a person who takes the reading should not be changed.
11.0 CONCLUSION According to the experiments, can evaluate the pump characteristics and performances of single two pumps in series and two pumps in parallel at a fixed speed. Pumps are used to convert mechanical energy into fluid energy and allow liquids to be moved from one place to another. From this experiment, can understand fully the types of pumps available and their different characteristics. Measurements of head, flow, speed and torque allow the performance of each pump to be determined and compared. Therefore, the experiments assumed success.
12.0 REFERENCES
Roberson, J.A, Cassidy, J.J & Chaudry, M.H. (1998) ‘Hydraulic Engineering’, Wiley.
Ab Aziz Abdul Latiff, Hidraulik, Jabatan Kejuruteraan Awam Dan Alam Sekitar, Penerbit UTHM.
White Frank M.(1979). Fluid Mechanics. Mc Graw, Hill.University of Rhode Island. United States of America, pg 636 - 642.
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