rephrase

Friction Loss

THERMAL AND FLUID

EXPERIMENT

FRICTION LOSS ALONG A PIPE AND MINOR LOSSES ACROSS VALVES, BENDS, AND SUDDEN CHANGES IN AREA

by

Table of Contents

List of Symbols….…..…………………………………………………………….…………… 3

Abstract.…....………………..………….………………………………………………….……. 4

Results Summary.....…………..…………………………………………………………..............5

Discussion and Conclusions ………………………………………………….............................12

Appendices .…………………………………………................................................................. 13

List of Symbols

Symbol Description Units

A area m2

D diameter m

g gravity m/s2

h convection heat transfer coefficient W/m2* K

L length m

m mass kg

ṁ mass continuity lbm/s

P pressure Pa

Pabs absolute pressure N/m2

Pgage gage pressure N/m2

Q volume flow rate m2/s

Re Reynolds number

t time s

T temperature K

strain in/in

V fluid velocity m/s

fluid density kg/m3

Abstract

The objective from this week’s lab experiment was to analyze the resistance of water through pipes. There are some factors that could have an impact on the results such as the bends in the pipes and the sudden changes of are in them. Also the friction of the pipes and the losses across the valves may have a difference too.

As a results to our calculations we found out that the fluid loses energy as it flows through the pipes, the reason after that is the drop in pressure. The density of the fluid, viscosity of water, shapes of pipes, changes in area and the dimensions of the pipe all have an influence on the pressure drop. We calculated the head loss in expansion and compression from the data obtained from our experiment. We also used the data to calculate Reynolds number, and Blasius friction factor.

Comparing our results to the standard results we found out that we did not have a high uncertainty error. The flow rate uncertainty came out to be 1.9%; also the head loss uncertainty was 2.8%. Also, Reynolds number and Blasius friction factor uncertainty came out to be 3.3% and 1.9% respectively.

Results Summary

1. Straight pipe– Dark Blue circuit, component A (length = 914.4 mm)

a) After calculating the head loss by using the formula

The following data was obtained:

After plotting this data with Q on the x-axis, the following plot was obtained:

Figure1

From the above graph, using the relation , the power of n is 3 .

b)From the data, after calculating the friction factor using

Where hl is the head loss, D is the diameter, L is the length of the pipe and g is gravity

The following results were produced:

After plotting Friction factor as a function of Reynolds number and Blasius Equation as a function of Reynolds number on the same graph the following was produced:

Figure2

2. Sudden Expansion-(Light Blue circuit, pipe expander E – D-13.6 mm X D-26.4 mm)

a) From the flow data, after calculating measured head loss using

Δhtest=h8-h7

And calculated head rise, first with no head loss and then with head loss

The following results were produced:

The loss coefficient Kl was 0.5.

The following is the graph with these results:

Figure3

3. SUDDEN CONTRACTION – (Light Blue circuit, pipe reducer F – 26.4 mm X 13.7 mm)

From the flow data, after calculating measured decrease in head using

Δh=h9-h10 and calculated head decrease, the following results were obtained:

The loss coefficient Kl was 0.376. The graph with these plotted:

Figure4

1. BENDS

Figure5

Figure6

2. VALVES

Figure 7

Discussion and Conclusion

In this experiment we had to study or observe the friction loss of water in the pipes due to the pipes’ shapes, valves, bends..etc. From the calculated friction loss we could calculate the head loss of the water, which is the primary reason to this experiment.

After calculating the Sudden Expansion through the pipes we figured out that the head rise with head loss was lower than the rise without the head loss. When it comes to Sudden Contraction of the pipe, we found out that the head decrease with the head loss was higher than the head decrease without the head loss. We saw a major drop in pressure, which could be because of the change of the cross sectional area of the pipe that changes suddenly.

Gravity has a role on the pressure of the water in the pipes, from our calculations we saw that the bends in the pipes caused a drop in the pressure, again. Which could be because of gravity.

Comparing our results to the standard results we found out that we did not have a high uncertainty error. The flow rate uncertainty came out to be 1.9%; also the head loss uncertainty was 2.8%. Also, Reynolds number and Blasius friction factor uncertainty came out to be 3.3% and 1.9% respectively. Moreover, the uncertainty in the velocity was 5.2%. So, as a result we can see clearly that the numbers that we came up with were reasonable despite the uncertainty factors such as timing, water flow speed or even simple human errors.

To some up, we can say that our calculations were similar to that of the theoretical values which gives us a reasonable explanation to why we got these values. Now we have a better understanding to how friction loss of the water flowing through the pipes have a huge factor on the calculation s and eventually the final results. The experience that we got from this lab experiment will defiantly help us in the future.

APPENDICES

EXPERIMENTAL DATA

THEORY

PROCEDURE

CALCULATIONS

ERROR ANALYSIS

REFERENCE

APPENDIX A

EXPERIMENTAL DATA

APPENDIX B

THEORY

In this experiment we are to analyze the friction loss along a pipe and losses across valves. In addition, we are to analyze sudden changes in area and using the flow rate of water along with the dimensions of the pipes, the head loss and head without loss along points of the pipes and using Bernoulli equation