ECE3421 CHEMICAL ENGINEERING LAB II EXPERIMENT 5
:
SERIES AND PARALLEL PUMP
Candidate’s Name
: Divaan Raj Karunakaran
Student ID
: SCM 026024
Group Member’s Name
: Yuga Raaj A/P J.Balar Viveta Priyaa A/P Selvarajan Thivya A/P P.Maran Alaa adnan Mohammed Salleh
Lecturer/ Supervisor
:
Dr. Yap Pow Seng
Date of Submission
:
24 / 02 / `2014
ABSTRACT
The purpose behind conducting this experiment on the two different pump system , the single pump system and the identical pump system ( series and parallel pump ) is to observe how will such a pump system operate and the characteristics behind its way of operation. But as of the main objective to experiment on the different pump systems is to differentiate the flow rate and pressure head of a single pump and of two other identical pumps which was run in series and parallel. In our experiment, we have used the centrifugal pump to determine the flow rates and the pressure head of the pumps. A very common system used to transfer liquids will be a centrifugal pump, as it is very quiet while operating in a way that in produces less friction and the noise production is lower. Also it takes up very little operating and maintenance costs, while it takes up very little floor space and create a uniform, nonpulsating flow. As we are experimenting manually on the different pump systems, this is to actually measure the performance of a centrifugal pump and to compare the results with the theoretical predictions. Besides all these, this experimental results will be helpful to even investigate the affinity laws for pumps.
INTRODUCTION
Almost in every industry and engineering fields, right from feeds to reactors or distillation columns to pumping storm water uses the aspects of pumps. Pumps are used to transfer fluid in a system, either at the same elevation or to a new height. The height to which the fluid will be pumped is responsible for the flow rate needed. Every pump has its head discharge relationship that is inversely proportional for instance if a higher flow rate is needed, then lesser pressure head will be produced by the pump, and vice versa. Usually the pump manufacturers will provide this head - discharge relationship, also known to be the pump characteristic curve. A centrifugal pump converts the input energy to kinetic energy in the liquid by accelerating the liquid by a revolving device as an impeller. Fluids enter the pump via eye of the impeller which rotates at high speed. The fluid is accelerated radically outward from pump chasing. A vacuum is created at the impellers of the eye that continuously draws more liquid into the pump. The energy created by the pump is a kinetic energy according to the Bernoulli equation. The energy transferred to the liquid corresponds to the velocity of the impeller. The faster the impeller revolves, the higher the velocity of the liquid energy transferred to the liquid. The basic operation of centrifugal pumps is to explore the flow rates and pressure head of a single pump and of two identical pumps that operate in series or in parallel. When pumps are arranged in series their resulting pump performance curve is obtained by adding their heads at the same flow rate. When pumps are arranged in parallel their resulting performance curve is obtained by adding their flow rates at the same head.
Schematic Diagram: Series pump
Schematic Diagram: Parallel pump
3.1 Overall Dimensions Height: 700mm Width : 650mm Depth: 1100mm
3.1 General requirements Electrical: 240VAC, 1-phase, 50Hz Water: clean tap water
3.2 Installation Installation procedures: 1. The unit was unpacked and placed on a table close to the single phase electrical supply. 2. The equipment was placed on top of a table and the equipment was level with the adjustable feet. 3. All the parts inspected and instruments on the unit and make sure that it is in proper condition. 4. The equipment was connected to the nearest power supply.
3.3 Commissioning procedures: 1. The equipment was installed according to the section 3.1. 2. All the valves are initially closed. 3. The sump tank was filled up with clean water until the water level is sufficient to cover the return flow pipe. 4. The test pump was tested according to section 5.1. 5. The pumps were checked like the flow meter and the gauges. Then, any leakage on the pipe line was identified. If there is any leakage it was fixed. 6. The pumps was turn off after the commissioning.
4.0 Experimental Procedures
4.1 General Start-up Procedures:
1. The circulation tank is filled with water up to at least the end of the pipe output is submerge with water. 2. The V5is in partial open position. 3. The main power supply is switched on. 4. The appropriate pump was selected and checked for following valve position.
Pump operation Single Serial Parallel
Running pump Pump1,P1 Both Pump,P1&P2 Both Pump, ,P1&P2
Open valve 1,4 1,3 1,2,4
Close valve 2,3 2,4 3
5. Turned on pump and slowly open V5 until maximum flowrate is achieved. Orientation Single Series Parallel
Minimum flowrate(LPM) 20 20 40
Maximum flowrate(LPM) 90 90 180
4.2 General Shut-down Procedures :
1. Turned off the pump. 2. The V5 is in fully close position. 3. The main power supply was switched on.
EXPERIMENT 1 : Single Pump Operation
Equipment Set Up: Fully close valve 2&3
Fully open valve 1&4
Variable parameter Valve 5
Pump ON Pump 1
Procedures: 1. 2. 3. 4.
The basic procedure as written is followed. Ensured that all setting follows the equipment set up. Slowly opened valve V5 until the flowrate reaches 20 LPM. The pressure reading on the pressure indicator was observed. The flowrate and pressure value was recorded when stable condition is achieved. 5. The observation was repeated by increasing the flowrate with increment by 10LPM until the flowrate reaches 90 LPM.
EXPERIMENT 2 : Series Pump Operation
Equipment Set Up:
Fully close valve 2&4
Fully open valve 1&3
Variable parameter Valve 5
Pump ON Both Pump
Procedures: 1. 2. 3. 4.
The basic procedure as written is followed. Ensured that all setting follows the equipment set up. Slowly opened valve V5 until the flowrate reaches 20 LPM. The pressure reading on the pressure indicator was observed. The flowrate and pressure value was recorded when stable condition is achieved. 5. The observation was repeated by increasing the flowrate with increment by 10LPM until the flowrate reaches 90 LPM.
EXPERIMENT 3 : Parallel Pump Operation
Equipment Set Up:
Fully close valve 3
Fully open valve 1&2&4
Variable parameter Valve 5
Pump ON Both Pump
Procedures: 1. 2. 3. 4.
The basic procedure as written is followed. Ensured that all setting follows the equipment set up. Slowly opened valve V5 until the flowrate reaches 40 LPM. The pressure reading on the pressure indicator was observed. The flowrate and pressure value was recorded when stable condition is achieved. 5. The observation was repeated by increasing the flowrate with increment by 20LPM until the flowrate reaches 180 LPM.
RESULTS
Rotameter (FI1) LPM
20 30 40 50 60 70 80 90
Pressure Gauge 1 (PI1) kgf/cm2 Analogue (PI1) Digital (PI1) kgf/cm2 kgf/cm2 0.00 1.07 0.00 1.07 0.00 1.07 0.00 1.06 0.00 1.05 0.00 1.05 0.00 1.04 0.00 1.04
Pressure Gauge 2 (PI2) kgf/cm2 Analogue (PI2) Digital (PI2) kgf/cm2 kgf/cm2 2.10 3.14 2.10 3.08 2.00 3.03 2.00 2.97 1.80 2.89 1.80 2.79 1.70 2.70 1.60 2.59
Table 6: Result of Experiment 1 ANALOGUE 2.10 2.10 2.00 2.00 1.80 1.80 1.70 1.60
PI2 – PI1 DIGITAL 2.07 2.01 1.96 1.91 1.84 1.74 1.66 1.55
Table 6.1: Result of Experiment 1 Rotameter (FI1) LPM
20 30 40 50 60 70 80 90
Pressure Gauge 1 (HI) kgf/cm2 Analogue Digital (HI) (HI) 2 kgf/cm kgf/cm2 0.00 1.06 0.00 1.06 0.00 1.05 0.00 1.04 0.00 1.04 0.00 1.03 0.00 1.02 0.00 1.00
Pressure Gauge 3 (PI3) kgf/cm2 Analogue Digital(PI3) (PI3) kgf/cm2 2 kgf/cm 2.10 5.16 2.10 3.07 2.00 3.00 1.90 2.92 1.85 2.84 1.80 2.76 1.70 2.66 1.60 2.53
Table 7: Result of Experiment 2
Pressure Gauge 4 (PI4) kgf/cm2 Analogue Digital (PI4) (PI4) 2 kgf/cm kgf/cm2 4.20 5.09 4.20 5.00 4.00 4.86 3.90 4.72 3.70 4.57 3.60 4.44 3.40 4.24 3.20 4.08
PI3 – HI ANALOGUE 2.10 2.10 2.00 1.90 1.85 1.80 1.70 1.60
PI4- H1 ANALOGUE 4.20 4.20 4.00 3.90 3.70 3.60 3.40 3.20
DIGITAL 4.10 2.01 1.95 1.88 1.80 1.73 1.64 1.53
DIGITAL 4.03 3.94 3.81 3.68 3.53 3.41 3.22 3.08
Table 7.1: Result of Experiment 2
Rotamete r (FI1) LPM
40 60 80 100 120 140 160 180
Pressure Gauge 1 (PI1) kgf/cm2 Analogu e (PI1) kgf/cm2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Pressure Gauge 2 (PI2) kgf/cm2
Digital(PI1 ) kgf/cm2
Analogue(PI2 ) kgf/cm2
Digital(PI2 ) kgf/cm2
1.06 1.05 1.05 1.04 1.03 1.03 1.02 1.00
2.10 2.00 2.00 1.90 1.80 1.80 1.70 1.60
3.08 3.02 2.97 2.90 2.83 2.75 2.66 2.55
Pressure Gauge 4 (PI4) kgf/cm2 Analogu e (PI4) kgf/cm2 2.10 2.10 2.00 2.00 1.90 1.80 1.70 1.60
Digital(PI4 ) kgf/cm2 3.03 2.98 2.93 2.87 2.77 2.71 2.62 2.51
Table 8: Result of Experiment 3 PI2 – PI1 ANALOGUE 2.10 2.00 2.00 1.90 1.80 1.80 1.70 1.60
DIGITAL 2.02 1.97 1.92 1.86 1.80 1.72 1.64 1.55
PI4- PI1 ANALOGUE 2.10 2.10 2.00 2.00 1.90 1.80 1.70 1.60
Table 8.1: Result of Experiment 3
DIGITAL 1.97 1.93 1.88 1.83 1.74 1.68 1.60 1.51
DISCUSSION
From the results obtained in this experiment, it is noticeable that the efficiency would depend on the species of the pump. As shown in the graph, we can conclude that as flow rate increases the pressure in each pump decrease either it is single, series or parallel pump. Efficiency of the pumps in series is higher than in parallel. The efficiency of the pumps in series is better in lower flow rate and higher head delivered and pumps in parallel is better for high flow rates and low head delivered
The first experiment done for the single pump system, the results of it clearly shows that as the flow rate of water increases, the pressure at gage 1 and pressure at gage 2 decreases. Somehow, there’s a slight difference in the magnitude of the pressure difference between the reading shown in the analogue and the digital meter. The pressure difference is graphed below :
Pressure difference vs Flow rate 2.5 2 PI2- PI1 (kgf/cm2)
1.5 ANALOGUE
1
DIGITAL 0.5 0 20
30
40
50
60
70
80
90
Rotameter (FI1) LPM
Graph 1.0 Pressure difference versus water flow rate for single pump
The second experiment was conducted for the two identical pumps in a series system. In this experiment quite a similar results was seen as that to the single pump system. As the flow rate is being increased, the pressure in gage 1 decreases also the pressure at gage 3 and 4 decreased with the increase in the water flow rate. The pressure difference between gage 3 and gage 1 and the pressure difference between gage 4 and gage 1 are shown in the graphs below :
Pressure difference vs Flow rate 4.5 4 3.5 3 (PI3 - HI) 2.5 (kgf/cm2) 2 1.5 1 0.5 0
ANALOGUE DIGITAL
20
30
40
50
60
70
80
90
Rotameter (FI1) LPM
Graph 2.0 Pressure difference ( PI3 - HI) versus water flow rate for series pump
Pressure difference vs Flow rate 4.5 4 3.5 3 2.5 (PI4 - HI) (kgf/cm2) 2 1.5 1 0.5 0
ANALOGUE DIGITAL
20
30
40
50
60
70
80
90
Rotameter (FI1) LPM
Graph 2.1Pressure difference (PI4 – HI) versus water flow rate for series pump
While the third experiment we did was on an identical pump too which was run in a parallel system. The results of this experiment shows not much of a difference to the previous single and series pump system experiments we did. At gage 1, pressure decreased almost significantly same as the single and series pump. At gage 2 and gage 4, pressure again decreased as the water flow rate increases. Pressure Gage 4 in series pump has a higher pressure than the pressure gage 4 in a parallel pump. The difference in pressure between pressure gage 2 and 1 and the difference in pressure between pressure gage 4 and 1 are shown below :
Pressure diffeence vs Flow rate 2.5 2 (PI2 - PI1) (kgf/cm2)
1.5 ANALOGUE
1
DIGITAL 0.5 0 40
60
80
100 120 140 160 180
Rotameter (FI1) LPM
Graph 3.0: Pressure difference (PI2 – PI1) versus water flow rate for parallel pump
Pressure diffeence vs Flow rate 2.5 2 (PI4 - PI1) (kgf/cm2)
1.5 ANALOGUE
1
DIGITAL 0.5 0 40
60
80
100 120 140 160 180
Rotameter (FI1) LPM
Graph 3.1: Pressure difference (PI4 – PI1) versus water flow rate for parallel pum
CONCLUSION
The pressure gradually decreases as the flow rate increases. A higher flow rate can be obtained when pumps are connected in series. Therefore, pumps in parallel mainly used because the flow is large. Pumps in series are not generally used because the maximum shut head of pump is additive and results in high design pressure. As an overall conclusion, from the results obtained in this experiment, it is noticeable that the efficiency would depend on the species of the pump. As shown in the graph, we can conclude that as flow rate increases the pressure in each pump decrease either it is single, series or parallel pump. Efficiency of the pumps in series is higher than in parallel. The efficiency of the pumps in series is better in lower flow rate and higher head delivered and pumps in parallel is better for high flow rates and low head delivered
REFERRENCE
Berham, P.P., Crawford, R.J., Armstrong, C.G. 1996, Mechanism of Engineering Materials, 2nd Edition, Pearson Education Limited, china.
Hibbeler, R.C. 2005, Mechanics of Materials, 6th Edition, Prentice Hall, Singapore.
Rama Durgaiah, 2002, Fluid Mechanics and Machinery, 1st Edition, New Age International (P) Ltd, India.
Hassan Sadiq. 18 March 2013. Centrifugal Pump Characteristic. [online] Available from: http://share.pdfonline.com/c901652df76f4bbaae22401aff9bb080/Sadiq%20report.htm [Accessed 18TH February 2014].
