Experiment_4 - Fluid Mechanics (CLD 10603) Experiment 4:...

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Unformatted text preview: Fluid Mechanics (CLD 10603) Experiment 4: Multi Pump Test Rig Experiment 4 Multi Pump Test Rig Objectives Determine the operating characteristic of different pumps in a contained unit. Understand the types of pumps in principle and design, and the selection of the appropriate pump for a particular application for optimal operation. Overview Pumps are of a major concern to most engineers and technicians. The types of pump vary considerably in principle and design, and the selection of the appropriate pump for a particular application is essential for satisfactory operation. This experiment allows students to measure the operating characteristic of different pumps in a contained unit. This training unit incorporates appropriate pipe work and tanks to make the operation self‐ contained. The manually operated valves and pipe work are arranged for rapid and safe selection of any one‐test pump. All necessary instrumentation for measurement of flow, pump head, speed and power are included. In the experiments, students are able to operate three types of pump namely a Horizontal Single Stage Centrifugal Pump, a Positive Displacement Plunger Pump and a Positive Displacement Gear Pump. 1 Fluid Mechanics (CLD 10603) Experiment 4: Multi Pump Test Rig General Start ‐ Up Procedures Before conducting any experiment, it is necessary to do the following checking to avoid any misuse and malfunction of equipment. 1. Make sure that the water tank is filled with water up to at least 50%. 2. Make sure that the oil tank is filled with oil up to at least 50%. 3. Make sure that the RS 232 data cable is connected to the computer. 4. Switch on the main power supply located on the control panel. The instruments should light up. 5. Select the appropriate pump and flow meter according to the following combination. 6. Switch on the computer and monitor if you are using them to collect data and generate the characteristic curve. Pump Indication Flow Flow rate Diff. Pump Meter Pressure Head P1/P2 0 ‐100% FT 1 0 – 113.56 DPT 1 0 – 3 bar L/min P3 0 ‐100% FT 2 0 – 28.39 PT 1 0 – 20 bar L/min Types of Pump Process Hand Valve Hand Valve Pump Selection Selection OPEN CLOSE Switch Switch Horizontal Single P1 Water HV2, HV3, HV4 HV1, HV5, HV6, Stage Pump HV7, HV8 Plunger P2 Water HV2, HV5, HV6 HV1, HV3, HV4, Pump HV7, HV8 Gear P3 Oil HV10, HV11 HV9 Pump 2 Fluid Mechanics (CLD 10603) Experiment 4: Multi Pump Test Rig Important: i. Never operate the pumps when there is no liquid in the pipeline. It will cause serious damage to the pumps. ii. Always watch out for the direction of the motor impeller, it should follow the direction of the arrow on the pump. Data Acquisition System 1. 2. 3. 4. 5. 6. 7. 8. 9. Power the pump Test Rig first. Ensure that the cable between the computer and the Pump Test Rig is correctly connected. Switch on the power to the computer. Under Windows click on the Pump Test Rig icon. The program will startup automatically. The table consists of fifteen entries and a final entry at the bottom labeled ʹliveʹ‐ this is the live reading at that moment in time (online data). During an experiment, if you wish capture these data, click on the ʹRecordʹ button. The recording mechanism will capture at maximum 15 entries. After which it will try to replace the closest old entry found. These captured data could be saved in the form of a file. It could also be loaded later for review or to add a new entry. It is important that the user selects the correct pump before recording the data, as live data will be represented differently for each pump. 3 Fluid Mechanics (CLD 10603) Experiment 4: Multi Pump Test Rig Experimental Procedures Experiment 1 : Rotational Speed Vs Volumetric Flow rate. Performance Curve for a Centrifugal Pump Experimental Procedures 1 for P1 Please refer to the general start ‐ up procedures before conducting this experiment. 1. Press the START push button to start the pump. Set the motor speed to about 2800rpm using the speed control beside the speed 2. indicator. 3. Open HV2 fully so that the flow rate is at its maximum. 4. Record the flow rate once the readings are stable. (Refer Table 1) 5. Repeat steps 2 and 4 for the following speed readings of 2600, 2400, 2200, 2000, 1800, 1600, 1400, 1200, 1000, 800 and 600rpm. 6. The data collected using above procedure will enable you to plot the following characteristic curve: i. Rotational speed (N) Vs. Volume Flow (Q) Note: i. Please switch off the pump by pressing the stop push button at the end of experiment. ii. Adjust the potentiometer to its minimum setting (fully anti clockwise). 4 Fluid Mechanics (CLD 10603) Experiment 4: Multi Pump Test Rig Experiment 2: Other Performance Curve for a Centrifugal Pump Experimental Procedures 2 for P1 Please refer to the general start ‐ up procedures before conducting this experiment. 1. Press the START push button to start the pump. 2. Set the motor speed to maximum (2800rpm) using the speed control beside the speed indicator. 3. Set HV2 at full opening so that the output flow rate is maximum and record the readings for the flow rate, the differential pressure, the power and speed once the readings are stable. (Refer Table 2) 4. Repeat step 3 with the following flow rate of output 70%, 60%, 50%, 40%, 30%, 20%, 10%. You can try any other intermediate reading. 5. The data you have collected will enable you to analyze the following characteristic curve: Vs Volume Flow rate (Q) i. Motor Input Power (PMi) ii. Pump Total Head (H) Vs Volume Flow rate (Q) Vs Volume Flow rate (Q) iii. Pump Power Output (Po) iv. Pump Power Input (Pi) Vs Volume Flow rate (Q) v. Pump Efficiency (ETA) Vs Volume Flow rate (Q) Vs Volume Flow rate (Q) vi. Overall Efficiency (ETAgr) Note: i. Please turn off the pump by pressing the stop push button at the end of experiment. ii. Adjust the potentiometer to its minimum setting (fully anti clockwise). 5 Fluid Mechanics (CLD 10603) Experiment 4: Multi Pump Test Rig Experiment 3 : Rotational Speed Vs Output Pressure Performance Curve for a Positive Displacement Pump Experimental Procedures 1 for P2 and P3 Please refer to the general start‐up procedures before conducting this experiment. 1. Press the START push button to start the pump. 2. Adjust the potentiometer beside the speed indicator, set the motor speed to its maximum (i.e. About 950 rpm for P2 and 1500 rpm for P3) 3. Slowly adjust the HV2 for P2 and HV 11 for P3 so that the pump head (pressure) is at 90% for P2 and 70% for P3. 4. Record the flow rate once the readings are stable.(Refer Table 3a & 3b) 5. Repeat steps 2 and 4 for the following motor speed readings of P3 = 1300, 1200, 1100, 1000, 900, 800, 700, 600, 500, 400 rpm and P2 = 950, 900, 850, 800, 750, 700, 650, 600, 550 rpm. 6. The data you have collected will enable you to plot the following characteristic curve. i. Rotational Speed (N) Vs. Output Pressure (Pr) Note: i. Please turn off the pump by pressing the stop push button at the end of experiment. ii. Adjust the potentiometer to its minimum setting (fully anti clockwise). Warning: Do not close the HV2 completely when P2 is running. This may cause serious damage to the instrument. 6 Fluid Mechanics (CLD 10603) Experiment 4: Multi Pump Test Rig Experiment 4 : Other Performance Curve for a Positive Displacement Pump Experimental Procedures 2 for P2 and P3 Please refer to the general start‐up procedures before conducting this experiment. 1. Press the START push button to start the pump. 2. Adjust the potentiometer beside the speed indicator, set the motor speed to its maximum (i.e. About 950 rpm for P2 and 1500 rpm for P3). 3. Slowly adjust the HV2 or HV 11 so that the pump head (pressure) is at 90% for P2 and 70% for P3, record the flow rate, differential pressure, power and speed once the readings are stable.(Refer Table 4a & 4b) 4. Repeat step 3 with the following pump head readings of P2 = 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10% and P3 = 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 10%. You can try any other intermediate reading but never try to close the HV2 or HV 11 fully. This is to ensure that the existing pressure develop in the pipeline doesn’t exceed the limit. 5. The data you have collected will enable you to plot the following characteristic curve; Vs Output Pressure (Pr) i. Motor Input Power (PMi) ii. Volume Flow (Q) Vs Output Pressure (Pr) iii. Pump Power Output (Po) Vs Output Pressure (Pr) iv. Pump Power Input (Pi) Vs Output Pressure (Pr) v. Pump Efficiency (ETA) Vs Output Pressure (Pr) Vs Output Pressure (Pr) vi. Overall Efficiency (ETAgr) vii. Volumetric Efficiency (ETAv) Vs Output Pressure (Pr) 7 Fluid Mechanics (CLD 10603) Experiment 4: Multi Pump Test Rig Note: i. ii. Please turn off the pump by pressing the stop push button at the end of experiment. Adjust the potentiometer to its minimum setting (fully anti clockwise). Warning: Do not close the HV2 completely when P2 is running. This may cause serious damage to the instrument. Results Record the data collected for experiment 1 in the table below. Table 1: Rotational Speed and Flow rate for P1 Speed (RPM) Flow rate (%) 8 Fluid Mechanics (CLD 10603) Experiment 4: Multi Pump Test Rig Record the data collected for experiment 2 in thetable below. Table 2: Flow rate, Speed, Differential Pressure and Power for P1 Flow rate % Record the data collected for experiment 3 in the table below. Table 3 a: Rotational Speed and Differential Pressure for P2 Speed (RPM) 950 900 850 800 750 700 650 600 550 Differential Pressure (%) Speed RPM Diff. Pressure % Power kW 9 Fluid Mechanics (CLD 10603) Experiment 4: Multi Pump Test Rig Table 3 b: Rotational Speed and Differential Pressure for P3 Speed (RPM) 1300 1200 1100 1000 900 800 700 600 500 400 Record the data collected for experiment 4 in the table below. Table 4 a: Pressure, Flow rate, Speed and Power for P2 Pressure % 90 80 70 60 50 40 30 20 10 Flow rate % Speed RPM Power kW Differential Pressure (%) 10 Fluid Mechanics (CLD 10603) Experiment 4: Multi Pump Test Rig Table 4 b: Pressure, Flow rate, Speed and Power for P3 Pressure % 70 65 60 55 50 45 40 35 30 25 20 10 Flow rate % Speed RPM Power kW 11 Fluid Mechanics (CLD 10603) Experiment 4: Multi Pump Test Rig List of Abbreviation Symbol N PMI H Q Pi P o Pm Zc1 Zc2 ETA ETAgr ETAv ρw ρoil DP Pr g Pp1min Pp2min Pp3min Vigar Vipiston ZG1 ZG2 Description Rotational Speed Motor Input Power Pump Total Head Volume Flowrate Pump Power Input Pump Power Output Pump Mechanical Power Inlet Distance From Datum (water) Outlet Distance From Datum (water) Pump Efficiency Overall Efficiency Volumetric Efficiency Density of Water Density of Oil Differential Pressure Pressure Gravity Pump 1 Power at No Load (50 Hz) Pump 2 Power at No Load (50 Hz) Pump 3 Power at No Load (50 Hz) Volume Displacement for Gear Pump Volume Displacement for Plunger Pump Inlet Distance From Datum (oil) Outlet Distance From Datum (oil) Constant Value 180 mm 860 mm 1000 910 9.81 70 60 50 6.309 x 10‐6 2.09 x 10‐5 64 mm 380 mm Unit RPM W m m3/hr W W W m m % % % kg/m3 kg/m3 % % m/s2 W W W m3/rev m3/rev m m 12 Fluid Mechanics (CLD 10603) Experiment 4: Multi Pump Test Rig Formula for Calculation of Variables Horizontal Single Stage Centrifugal Pump/ Plunger Pump ⎛ 113.56 x 60 ⎞ Volumetric flow rate, m3/hr Q = (q/100) x ⎜ ⎟ ⎠ ⎝ 1000 4 ⎛ DP ⎞ ⎛ 3 x 10.2 x 10 Pump Total Head, m H = (Zc 2‐ Zc 1) + ⎜ ⎟x⎜ ρw g ⎝ 100 ⎠ ⎜ ⎝ Pump Power Output, W Pump Power Input, W Pump Efficiency, % Overall Efficiency, % ETA gr= Po x 100 PMI ⎞ ⎟ ⎟ ⎠ Po = (ρwg HQ) / 3600 Pi = (PMI – P1min) or (PMI – P2min) ETA = Po x 100 Pi * For Plunger Pump Only Volumetric Efficiency, % ETAv = Q x 100 Vi x N x 60 Positive Displacement Gear Pump Volumetric Flow rate, m3/hr Pump Total Head, m Pr ⎛ 20 x 10.2 x 10 4 H = ZG2 – ZG1 + x⎜ ρ oil g 100 ⎜ ⎝ Q = q x 28.39 ÷ 10 3 x 60 100 ⎞ ⎟ ⎟ ⎠ Pump Power Output, W Po = (ρoil g HQ) / 3600 13 Fluid Mechanics (CLD 10603) Experiment 4: Multi Pump Test Rig Pump Power Input, W Pump Efficiency, Pi = PMI – P3 min ETA = Po x 100 % Pi Overall Efficiency, 100% Volumetric Efficiency, % Note: 1 GPM 1 bar ETA gr = Pump Power Output x 100 Motor Power Input Po x 100 PMI = ETAv = Q x 100 Vi x N x 60 = 3.7854 LPM = 10.2 mH2O Discussion Plot all the characteristic curves which have been stated in all the experiment conducted. Comments the plotted graphs in terms of their relationships between the y – axis and the x – axis 14 Fluid Mechanics (CLD 10603) Experiment 4: Multi Pump Test Rig Tutorial 1. 2. What is the difference between dynamic pump and positive displacement pump? 3. List down three factors which influence the choice of pump for a particular operation. Define pump. 15 Fluid Mechanics (CLD 10603) Experiment 4: Multi Pump Test Rig Conclusion References 1. White, F.M. Fluid Mechanics 4th Ed. McGraw Hill 2. McCabe, W.L., Smith, J.C and Harriot Unit Operations of Chemical Engineering 5th Ed. McGraw Hill 3. John F. Douglas (2001). Fluid Mechanics. 4th Edition , Prentice Hall 4. Joseph B. Franzini (2002). Fluid Mechanics. 10th Ed. McGrawHill 5. Noel de Nevers (1991). Fluid Mechanics for Chemical Engineers. 2nd Ed. McGraw Hill 6. John A. Roberson (2001). Engineering Fluid Mechanics. Wiley 16 ...
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