[예비 / 결과레포트] 레이놀즈 수 측정 실험

소개글

[예비 / 결과레포트] 레이놀즈 수 측정 실험에 대한 보고서 자료입니다.

목차

1. Objective
2. Theory
3. Apparatus
4. Chemistry
5. Procedure
6. Attention
7. Results
8. Discussion
9. Reference

본문내용

ontinuously and observe the continuous phenomenon closely. But the ink was little insufficient, so we dropped small amount of ink and captured a moment. In my opinion, If the background of pipe was covered by white color, we could observe the current of ink clearly. And we couldn't distinguish the degree of dispersion between transient flow and turbulent flow clearly. Once we measured the velocity of laminar flow, and made the velocity sufficiently fast and measured the velocity. Laminar and turbulent was different quietly, so we could do experiment more certainly. And finally we controlled the velocity in between laminar and turbulent. The dispersion was little weaker than turbulent flow and we judge that this flow is transient flow. As a result of this experiment, we got the above data. In theory, under the Reynolds Number 2000, it is defined laminar flow. Our result shows that the Reynolds Number is 252.9 in the laminar flow and 4380.4 in turbulent flow. It makes a sens for laminar flow and turbulent flow by compared the theory. Lastly, Reynolds Number is 2180.4 in transient flow. It is not certain that flow which we saw was real transient flow. Because in theory, it is normally accepted that transition from turbulent back to laminar flow occurs at a Reynolds Number between 2000 and 2300. Our result of 2180.4 is contained in transition range between laminar and transition flow. I thought that this result can be varied by experiment condition(eg. roughness and shape of pipe) and another method of experiment. But one fact is definite that 2180.4 is larger than 2000. Therefore our result of transient flow makes a sens at least possibly.
There is a manner to do more clear experiment. If we can control the velocity of water accurately by some pump, we can also control the Reynolds Number freely. At the same condition of environment, we can adjust the velocity of water at 0.102m/s to make Reynolds Number 2000. And then we can compare the flow shape of ink in this border and make result more certain. But we should control the velocity of fluid by the valve, it is hard to control the desired Reynolds Number. However although we can adjust the velocity freely, it is hard to find the border between transition and turbulent flow. Because as we can see in figure 1, It depends on the condition of pipe and also a division of them is ambiguous. In conclusion, we can't predict the border between laminar and transition or between transition and turbulent accurately, but we can predict the flow conditions in pipe approximately by using this Reynolds Number. Therefore I think that this is meaning of our experiment.
9. Reference
- Fluid Mechanics for Chemical Engineers, Second edition, by James O.Wilkes
- Chemical Engineering Laboratory Ⅱ, SungKyunKwan Univ. chemical Engineering.
- http://www.grc.nasa.gov/WWW/BGH/reynolds.html
- http://galileo.phys.virginia.edu/classes/311/notes/fluids2/node4.html
- http://video.google.com/videoplay?docid=1827702182265329855#

키워드

레이놀즈넘버,   레이놀즈,   레이놀즈수,   레이놀드,   레이놀드넘버,   레이놀드수,   reynold number