LAB report OZ PDF

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Description

Introduction Pumps are used in almost all aspects of industry and engineering from feeds to reactors and distillation columns in chemical engineering to pumping storm water in civil and environmental. They are an integral part of engineering and an understanding of how they work is important. Centrifugal pump is one of the most widely used pumps for transferring liquids. This is for a number of reasons. Centrifugal pumps are very quiet in comparison to other pumps. They have a relatively low operating and maintenance costs. Centrifugal pumps take up little floor space and create a uniform and nonpulsating flow. The Serial & Parallel Pump apparatus is specially designed to demonstrate to students the operating characteristics of centrifugal pump in series, parallel or single pump operation. This training unit operates in close loop. This equipment will explore the relationship between pressure head and flow rate of a single pump and of two identical pumps that run in series or in parallel. When identical pumps run in series, the pressure head is approximately doubled but the flow rate remains the same. When pumps are run in parallel the flow is increased but the pressure head produced is approximately the same as a single pump. This equipment also allows the study of efficiency of a pump. The energy in this experiment is put through two transformations. First, the electrical energy, which is the energy put into the system, is transferred to mechanical energy, which is the energy required to move the shaft and impeller. Second, the mechanical energy is transferred into energy of the fluid. This is accomplished through the pump rotation, which transfers the velocity energy of the water to pressure energy. The overall efficiency is the product of the mechanical (shaft) efficiency and the thermodynamics efficiency 1 .

Procedure

1 http://infinit-technologies.com/our-products/fm-1849-23-series-and-parallel-pump-apparatus/

a) Both pumps must be used at the same setting in this experiment to ensure identical performance. As the speed of pump is fixed at its design operational point, pump 1 should be set to match - select 80% for a 50Hz electrical supply, or 100% for 60 Hz. b) Allow water to circulate until all air has been flushed from the system. c) Open pump 2 outlet valve, close pump 1 outlet valve and wait for any air to circulate out of the system. d) Select the (Go) icon to record the sensor readings and pump settings on the results table of the software. e) Close the gate valve to reduce the flow by a small increment. Select the (Go) icon again. f) Continue to close the gate valve to give incremental changes in flow rate, recording the sensor data each time. g) After taking the final set of data, fully open the gate valve again. Pumps in parallel exercise may be performed immediately after this experiment without closing the software; otherwise, save the results and ensure they are available for exercise B when required. (It may also be advisable to save the results from this exercise before starting exercise B even if continuing straight on, to ensure that the data is not lost in the event of a computer failure. The results sheet may be overwritten with the combined results once exercise B has been completed). 2

Objectives We are going to start the pump once in series and once in parallel to get some numbers to put in equations to get some of the impotent results such the efficiency and pump head .

Results and discussion

2 Series and parallel pumps by Eng. Mohammed mousa (some correction has written)

Observations : Series Pump speed 2309 2307 2305 2302 2304

Volume F 105 95 78 51 20

Pressure 1 0.27 0.23 0.23 0.22 0.21

Pressure 3 0.8 0.9 1.2 1.4 1.7

Electrical power 715.2 707.6 681.2 659.4 584.1

Volume F 120 95 80 50 25

Pressure 2 1 0.9 0.8 0.4 0.8

Pressure 3 1.7 1.8 1.9 1.9 1.4

Electrical power 670.4 627.7 598.5 537.3 481.4

Parallel Pump speed 2436 2443 2448 2457 2465

Charts & results series P3 – p1 0.53 0.67 0.97 1.18

Pump head 5.4E+00 6.8E+00 9.9E+00 1.2E+01

Hydraulic power

Efficiency 12.97 14.99 18.51 15.21

Pump head 7.1E+00 9.2E+00 1.1E+01 1.5E+01

Hydraulic power

Efficiency 20.88 22.70 24.51 23.26

parallel P3 – p1 0.7 0.9 1.1 1.5

parallel I 1.60E+01 1.40E+01 1.20E+01 1.00E+01 8.00E+00 6.00E+00 4.00E+00 2.00E+00 0.00E+00 20

40

60

80

100

120

140

series I 1.40E+01 1.20E+01 1.00E+01 8.00E+00 6.00E+00 4.00E+00 2.00E+00 0.00E+00 10

20

30

40

50

60

70

80

90 100 110

series II 20 15 10 5 0 10

20

30

40

50

60

70

80

90

100 110

By the previous data and graphs we can see the difference between starting the pumps in series and the parallel .

Appendix : http://infinit-technologies.com/our-products/fm-1849-23-series-and-parallel-pump-apparatus/ Series and parallel pumps by Eng. Mohammed mousa (some correction has written)...