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2012 06 03

UNIVERSITY OF WINDSORDepartment of Mechanical, Automotive and Materials Engineering

FLUID MECHANICS II (92-320)

EXPERIMENT A: CENTRIFUGAL PUMP EXPERIMENT_________________________________________________________________________________

OBJECT: The objective is to experimentally determine the performance (head vs flowrate)characteristic curves for a variable speed centrifugal pump and show that the Affinity Laws

of Scaling apply.

APPARATUS:

a) GUNT HM150.04 Variable Speed Centrifugal Pump Test Facility and HM150 Basic HydraulicsBench as illustrated below.

b) stop watchRefer to the apparatus schematic supplied by the Graduate Assistant to identify the

1. Storage tank2.

Supply pump and ON/OFF switch3. RPM controller

4. Test pump and ON/OFF switch5. RPM-Watt readout and indicators6. Inlet and outlet pressure gauges7. Flow control valve8. Measurement tank and volume scale9. Drain valve

PROCEDURE:

1. Make sure that the drain valve is open and there is water in the storage tank.2. Turn on the test pump using the test pump ON/OFF switch.3. Make sure that the RPM-Watt Indicator is set to RPM and adjust the RPM of the test pump to

1200 RPM using the RPM controller and readout.

4. Close the flow control valve completely.5. Read and record the values of PIN and POUT (V, Q and CQ = 0 for this case)6. Fully open the flow control valve.7. Close the drain valve and, using the stopwatch and measurement scale, measure the time

required to collect 20 litres of water and record these values.

8. Read and record the values of PIN and POUT.9. Change the RPM to 1800 and repeat steps 4 to 8 inclusive.

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EXP. A - CENTRIFUGAL PUMP EXPERIMENT (Page 2 of 3)

GROUP # ________________ DATE: ______________________________________________________________________________________________

DATA REDUCTION:

As shown in class, a dimensional analysis of flow through a pump yields the following dimensionless

groups.

Head Coefficient = CP=P/(2D

2) = f( CQ, Re, /D)

where

P= pressure difference (P2 - P1)(Pa)

= fluid density (approximately equal to1000 kg/m3in this experiment)

= pump rotor angular velocity (rad/s)

N = number of rotor revolutions per minute (RPM)

D = pump rotor diameter (taken to be 0.1m in this case)

CQ = Capacity or Flow Coefficient = Q/D3

Re = Reynolds number= D2/

/D = Relative Roughnessand

Q = volume flow capacity (m3/s) = V/t

V = volume collected (in this experiment use 20 litres = 0.02m3)

t = time to collect volume= viscosity (Ns/m2)

= surface roughness (m)

Usually the viscous and roughness effects are negligible and CP= f( CQ)

N (RPM) P2(bar)

P1(bar)

P

(Pa)

= ( P2-P1)*105

(rad/s)

= N/30

CP

=P/(2D

2)

V

(m3)

Time

(secs)

Q

(m3/s)

= V/t

CQ

= Q/D3

1200 0.0 0.0 0.0

1200 0.02

1800 0.0 0.0 0.0

1800 0.02

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EXP. A - CENTRIFUGAL PUMP EXPERIMENT (Page 3 of 3)

GROUP # ________________ DATE: _____________

_________________________________________________________________________________

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.0E+00 5.0E-04 1.0E-03 1.5E-03 2.0E-03 2.5E-03 3.0E-03 3.5E-03 4.0E-03

Flow Coefficient, CQ

Head

Coefficient,

CH

1500

2000

RPM

QUESTIONS:

1. How do your data points compare with those points from the other angular velocities?

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2. List two possible reasons for error in the experimental results.

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GROUP MEMBERS:

Printed Name Duties Signature