8SUMMARYThe objective of this experiment is to understand the conversion of measured units of quantity to those of the variables necessary to calculate pump performance. To obtain the various characteristic curves for a centrifugal pump operating at inherent speed. And to demonstrate the operating characteristics of two pump running in a series and a parallel pumping installation.INTRODUCTIONCentrifugal pumps are the most common type of kinetic pump, and are used most often in applications with moderate-to-high flow and low head. As the workhorse of the chemical process industries (CPI), centrifugals are almost always more economical to own, operate and maintain than other types of pumps. Many hydraulic systems employ centrifugal pumps to move fluid through a piping system. These pumps all rely on centrifugal force as the fundamental principle by which they operate. An increase in the fluid pressure from the pump inlet to its outlet is created when the pump is in operation. This pressure difference drives the fluid through the system or plant. The centrifugal pump creates an increase in pressure by transferring mechanical energy from the motor to the fluid through the rotating impeller. The fluid flows from the inlet to the impeller centre and out along its blades. The centrifugal force hereby increases the fluid velocity and consequently also the kinetic energy is transformed to pressure.

PROCEDURE Lab 1.1Open inlet valve V fully and close the discharge valve V2 then start the pump (pump motor started under minimum load). Open discharge valve V2 fully, and allow the water to circulate until all air bubbles have dispersed. Select 'Diagram' and note the value of the volume flow indicated at the bottom of the screen. Gradually close discharge valve V2 until the volume flow is approximately half of the maximum reading.When the indicated readings of the 5 measured variables are reasonably constant, select the 'Take Sample' button from the menu-bar. Itnecessary to take three sets of results for this exercise. Now select the 'Tables' button from the menu-bar, and you will see the results of your test sample laid out as one row of a Table under one of two headings: 'Measured Variables' and 'Calculated Variables'. Take note the values of the measured variables your sample took, as follows: Differential pressure across orifice dPo [kPa]; Volumetric flow rate, Qv [dm3/s]; Differential pressure across pump 1 dPp1 [kPa]; Motor Input Power Pgr [W]; Motor speed, N[Hz]; Water Temperature T [oC].

Lab 1.2 and Lab 1.3I - Select maximum pump speed N1 by adjusting the power controller to 100% and open inlet valve V1 fully. Close discharge valve V2 then start the pump (pump motor started under minimum load). (Open discharge valve V2 fully and allow the water to circulate until all air bubbles have dispersed. Select 'Diagram' and note the value of the volume flow indicated at the bottom of the screen. Decide on suitable increments in flow to give adequate sample points (typically 15 points between zero and maximum flow). Close valve V2 to correspond to the condition of no flow i.e. Qv = 0. When the measured readings as indicated in the boxes on the schematic diagram are sufficiently steady, select 'Take Sample'. This represents the first point on the characteristic curve. Open valve V2 slightly, to give the first increment in volume flow at the bottom of the screen. When readings are steady enough, select 'Take Sample'. Repeat this step for a gradually increasing set of valve V2 openings, i.e., increasing values of flow Qv. The final sample point will correspond to valve V2 being fully open.

Lab 1.4

Select maximum pump speed N by adjusting the power controller to 100% on both pumps and open the inlet valves to both pumps fully. Close discharge valve V5 then start the pumps (pump motors started under minimum load). Open discharge valve V5 fully and allow the water to circulate until all air bubbles have dispersed. Click on the button 'Singlelparallel, on the 'Diagram' screen to set the configuration to single pump operation. Pump two on the diagram should be shadowed. Switch off pump two and set the valves as shown on the screen. Close Valve V5, to correspond to the condition of no flow i.e. Qv = 0. When the measured readings as indicated in the boxes on the schematic diagram are sufficiently steady, select 'Take Sample'. This represents the first point on the characteristic curve. Open valve V5 slightly, to give the first increment in volume flow at the bottom of the screen. When readings are steady enough, select 'Take Sample'. Repeat this step for a gradually increasing set of valve V5 openings, i.e. increasing values of flow Qv. The final sample point will correspond to valve V5 being fully open.

RESULTS Lab 1.1Data set 1Data set 2Data set 3

Differential pressure across orifice, dP0 [KPa]0.2050.120.103

Volumetric flow rate, Qv [dm3/s]0.0990.0810.057

Differential pressure across pump 1, dPp1 [KPa]71.54351.56317.617

Motor input power, Pgr [W]230.22204.35139.89

Motor speed, N[Hz]544627

Water temperature, T[C]18.91919.2

Table 1 Data from Lab 1.1. Data set 1Volumetric flow rate:

Head:

Power input:

Overall Efficiency:

Data set 2Volumetric flow rate:

Head:

Power input:

Overall Efficiency:

Data set 3Volumetric flow rate:

Head:

Power input:

Overall Efficiency:

Lab 1.2

Qv [m3/s]Head [m]Power Output, [W]Overall EfficiencyPower Input, Pe [W]

0.0001256.888.14.5180

0.0002036.5414.85.3279.24

0.0003935.2921.38.3256.63

0.0004465.2322.48.8254.54

0.0005035.1124.89.6258.33

0.0005464.9527.39.9275.75

Table 2 Data from Lab 1.2.

Graph 1 Centrifugal pumps characteristics

Lab 1.3 and 1.4Series ConfigurationParallel Configuration

Qv [m3/s]Head [m]Qv [m3/s]Head [m]

0.00015216.180.0001158.64

0.00033514.470.000248.08

0.00048412.420.0004887.64

0.0005311.310.000747.02

0.0006359.520.0008986.57

0.0007028.650.0009876.32

0.0007258.480.00125.92

0.0012025.58

Table 3 Data from Lab 1.3 and 1.4.

Graph 2 Head Capacity curves for single and series pumps.

Graph 3 Head Capacity curves for single and parallel pumps.DISCUSSIONSFrom the first part of experiments, the losses noted between the values found by equations and read by the software, occur because the friction of the water with the pipe, or could be originate from human mistakes and wrong dimensional analysis. In the graph 02, can be noted that when centrifugal pumps are connected in series we have each of the pumps putting energy into the pumping fluid then the result observed shows the resultant head as the sum of the individual heads. In the Graph 03 it can be note that when in parallel, the pumps can produce twice the flow of a single pump.CONCLUSIONSIn this lab, could be understand the pump performance, calculated from the equations. Could be obtained the characteristic curves for a centrifugal pump. And were demonstrated the operating characteristics of two pump running in a series and a parallel pumping installation compared with a single pump and could be noted that in parallel pump the flow is twice that a single pump and in a series pump the head is the sum of the heads in a single pump.

REFERENCES AND BIBLIOGRAPHY [1] _____. Pump Selection. Accessed in February 14th, 2014. [2] _____. Laboratory Manual. Regina, Saskatchewan. University of Regina. [3] _____. Centrifugal principles. Accessed in February 14th, 2014. [4] Grundfos Research and Technology. Understand the Basics of Centrifugal Pump Operation - Fluids/Solids Handling. Cep Magazine. May 2002 [5] FERNANDEZ, K. et al. The Centrifugal Pump.