Head Losses in Pipes

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  • Topic: Totaled, British H class submarine, HMS H4
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  • Published : January 4, 2011
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EXPERIMENT 1 – HEAD LOSSES IN PIPES
Introduction:
In this experiment, the aim is to find the losses of water flow in a pipe system.There are two types of losses. First the major losses which is caused by the the frictional effect of pipe. Second one is the minor losses which is caused by the turning points(corners) of pipes.

Apparatus:
• • • • • • 90° mitter bend 90° elbow bend 90° large radius bend Sudden enlargement in pipe diameter Sudden contraction in pipe diameter A pump to supply water

Theoritical Considerations:
To determine the minor losses in a water flow , some loss coefficients are used. These coefficients are detemined by experiments. Km is the coefficient that we have used. ℎ = ∗ ∗

hm gives the minor loss head in meters.

PROCEDURE:
When the system is at stagnant position pump is run. Then the heights of manometers are measured.After that to determine the discharge, the time is measured while a 10 lt of container is filling. Taking reading rapidly is important, otherwise the levels of manometer may change in time. The measurement point of manometer is represented in Figure 2.

1

RESULTS:
Minor loss comparison between theoretical and application values In the experiment minor loss between 5 and 6 is 6mm. If we calculate the theoretical value: 22.5 = 0.76 29.6 ℎ ℎ = 0.15 0.58 ℎ = 0.15 ∗ = 0.00257 2 ∗ 9.81 =

= 2.5

The experimental and the theoretical value did not fit. It may be an error of apparatus and wrong readings.

Minor loss at contraction is 40-12=28 mm.

2

h1 h2 h3 h4 h5 h6 h7 h8 h9 h10 total loss volume(lt) time(sec) Discharge(m3/s) G= bw h1-h2 h2-h3 h3-h4 h4-h5 h5-h6 h6-h7 h7-h8 h8-h9 h9-h10

1(mm) 2(mm) 3(mm) cross-section(mm) V1(m/s) v2(m/s) V3(m/s) 430.00 460.00 463.00 22.50 0.58 0.75 0.78 379.00 385.00 378.00 22.50 0.58 0.75 0.78 364.00 365.00 355.00 22.50 0.58 0.75 0.78 340.00 332.00 315.00 22.50 0.58 0.75 0.78 339.00 331.00 314.00 22.50 0.58 0.75 0.78 345.00 340.00 325.00 29.60 0.34 0.44 0.45 345.00 338.00 325.00 29.60 0.34 0.44 0.45 320.00 305.00 285.00 22.50 0.58 0.75 0.78 319.00 305.00 285.00 22.50 0.58 0.75 0.78 307.00 288.00 266.00 22.50 0.58 0.75 0.78 123.00 172.00 197.00 10.00 10.00 10.00 1st measurement 2nd measurement 3rd measurement 43.28 33.35 32.43 Q^2(lt^2/sec)= 0.0533857681 0.0899100675 0.0950837065 0.00023 0.000300 0.000308 9.81 Km1 2.96 0.87 1.39 0.06 0.00 0.06 0.70 Km2 2.59 0.69 1.14 0.03 0.21 0.00 0.59 Km3 2.77 0.75 1.30 0.03 0.00 0.00 0.62 Kavg 2.77 0.77 1.28 0.04 0.07 0.02 0.63 250,00 200,00 Loss(mm) 150,00 100,00 50,00 0,00 0,04 0,05 0,06 0,07 Q^2(lt^2/sec) 0,08 0,09 0,10

Total loss increases with increasing discharge

Total Loss vs. Q^2

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TOTAL HEAD(mm) 1.0000 447.21 488.99 1.5000 447.21 488.99 1.5001 396.21 413.99 2.0000 396.21 413.99 2.5000 396.21 413.99 2.5001 381.21 393.99 3.0000 381.21 393.99 3.5000 381.21 393.99 3.5001 357.21 360.99 4.0000 357.21 360.99 4.5000 357.21 360.99 4.5001 356.21 359.99 5.0000 356.21 359.99 5.5000 356.21 359.99 5.5000 350.75 349.68 6.0000 350.75 349.68 6.5000 350.75 349.68 6.5000 350.75 347.68 7.0000 350.75 347.68 7.5000 350.75 347.68 7.5001 337.21 333.99 8.0000 337.21 333.99 8.5000 337.21 333.99 8.5001 336.21 333.99 9.0000 336.21 333.99 9.5000 336.21 333.99 9.5001 324.21 316.99 10.0000 324.21 316.99

500,00

493.65 493.65 408.65 408.65 408.65 385.65 385.65 385.65 345.65 345.65 345.65 344.65 344.65 344.65 335.23 335.23 335.23 335.23 335.23 335.23 315.65 315.65 315.65 315.65 315.65 315.65 296.65 296.65

First Measurement

450,00 Head(mm)

400,00

350,00

300,00

250,00 1 2 3 EG 4 HG 5 6 7 8 9 10

500,00 450,00 Head(mm) 400,00 350,00 300,00 250,00 1 EG 2 HG

Second Measurement

3

4

5

6

7

8

9

10

reading points

4

HYDRAULIC head(mm) 1.0000 430.00 460.00 1.5000 430.00 460.00 1.5001 379.00 385.00 2.0000 379.00 385.00 2.5000 379.00 385.00 2.5001 364.00 365.00 3.0000 364.00 365.00 3.5000 364.00 365.00 3.5001 340.00 332.00 4.0000 340.00 332.00 4.5000...
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