Assessment - Surge and Water Hammer Coursework

Assessment Task:

You are required to write up the Warren truss Laboratory experiment using the data set generated during your own lab group.

The descriptor can be found at the end of this cover sheet.

Learning Outcomes

1. Use laboratory experiments to give context and improve the understanding of fundamental topics and enrich theoretical knowledge.

2. Gain an understanding of the principles of force equilibrium and use to analyse & design simple structures under various loading conditions

Experiment 1 - Pipe Surge

Aims

To compare the measured surge height and oscillation period with theoretical predictions

Procedure

1. Setup equipment shown in Figure 1

2. Close the Surge Value and the Water Hammer flow control valve (Figure 2).

3. Fully open the water supply on the Hydraulic Bench and start the pump. The reservoir will fill to a maximum level of approximately 620mm.

4. Reservoir and Surge Tower should read similar values (+/- 10mm)

5. In VDAS select the H405 layout then select the Pipe Surge experiment.

6. Click on the Initiate Communications with Device toolbar button. Check
Channel 1 trace of VDAS is a similar value to that shown on the scale next to Surge Tower (+/- 10mm).

7. In VDAS click on the Terminate Communications with Device toolbar.

8. Carefully open the Surge valve, allowing a small flow to pass along the Surge Pipe into the measuring tank of the Hydraulic Bench. Adjust the valve until the Surge Tower reading is approximately 550mm shown on its scale. This is called the Steady State Surge Level and should be lower than the ‘Reservoir Level'.

9. Allow up to a minute for the flow to stabilise and recheck the Steady State Surge Level remains at 550mm.

10. Use the Hydraulic Bench to measure the volume flow rate leaving the Surge supply pipe.

11. VDAS Click on the Initiate Communications with Device toolbar button and enter the Volume Flow Rate, Reservoir level and Steady State Surge Level shown on Channel 1 trace.

VDAS automatically calculates the flow rate velocity and subtracts the Steady State Surge Level from the Reservoir level to find the head loss along the supply pipe at each flow rate.

12. Shut the Surge value as quickly as possible. VDAS will show the oscillations

13. Wait at least 60 seconds for the oscillations to reduce to Zero. The flow has stopped so the Surge level should return to approximately the same value as the Reservoir.

14. Press Terminate Communications with Device toolbar button.

15. Use the cursors in VDAS to measure the Period and maximum Surge Height of the trace. Enter these values into the VDAS and record your data. VDAS automatically subtracts the Reservoir level from the Maximum Surge Height, Giving the Surge Amplitude.

16. Record the values in excel via the VDAS interface

17. Add a new data series and repeat the experiment with progressively lower Steady State Surge Levels of roughly 500mm, 450mm, 400mm, and 350mm.

18. Turn off water supply, open all valves and drain equipment.

Results Analysis

For each steady state surge level plot a graph of oscillations against time following value closure and discuss the variances.

Create a chart of Head loss (vertical axis) against Volume Flow to see the effects of pipe friction. Calculate the equation of the curve and compare it with the theory.

Show the calculation of the theoretical time period and compare it with the measured time period. Compare the results and comment
Create a chart of both experimental and theoretical surge amplitude (vertical axis) against volume flow. Compare and comment.
Discuss the impact surge pressures can have on a system and how they can be controlled.

Experiment 2 - Water Hammer

Aims

To compare the measured amplitude of pressure with theoretical predictions

To calculate the speed of the pressure surge along the pipe.

Procedure

1. Set up the equipment as shown in Figure 3.

2. Shut the surge valve and the water hammer flow control valve.

3. Fully open the water supply valve on the Hydraulic bench and start its pump to fill the reservoir to its maximum height of approximately 620mm.

4. Inset the valve rest tool to keep the quick-closing valve open.

5. Bleed air from the system using the quick-closing valve and retighten.

6. Fully open the water control valve to give maximum flow

7. Use the Hydraulic Bench to measure the flow rate from the water hammer pipe.

8. Click on the Initiate Communications with device toolbar button and enter the Volume Flow rate.

9. Hold the quick-close release valve and remove the testing tool.

10. Quickly press down the plunger on the top of the quick-closing valve. VDAS will capture the passage of the acoustic wave past each of the pressure transducers. Repeat if a representative trace is not seen.

11. Use the cursors to measure the time between the rising edge of the traces of channel 1 and 2 to see the time taken for the pressure to move from one transducer to the other and enter this value into VDAS. VDAS will calculate the acoustic velocity, the flow velocity and the theoretical pressure amplitude for water at a density of 1000kg/m3

12. Turn off water supply, open all valves and drain equipment.

Results Analysis
Compare the theoretical and measured acoustic velocity and pressure amplitude and discuss the engineering significance and implications of water hammer.

Submission:

Preparation and presentation of a standard written technical report, presenting all results, discussion and conclusion, including:

• Abstract/Summary of your work (consisting of your aims and objectives and how they were achieved, main findings and conclusions)

• Aims and Objectives of the experiment

• An introduction/background consisting of relevant theory only

• Image and description of apparatus

• Methodology (do not cut and paste the coursework descriptor)

• Data, results and graphs where appropriate (Calculations of forces derived from experimental measurement and theoretical forces from the method of joints)

• Comparison of results graphically and percentage difference.

• Conclusions (what do you conclude from the experiment, comments on the comparison between both sets of results and any information you have gleaned from lectures, background reading etc.)

• References (in accordance with USW Harvard guidelines.)

Attachment:- Surge and Water Hammer Coursework.rar