[예비 / 결과레포트] 관 부속품에 따른 압력강하 측정

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[예비 / 결과레포트] 관 부속품에 따른 압력강하 측정에 대한 보고서 자료입니다.

목차

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

본문내용

s bigger surface area so the friction is also larger. In this way we can interpret the Bernoulli's equation and head loss equation intuitively. On the other hand the head loss is less affected by the friction factor than other factors in condition of sudden expansion and contraction or other valves and pipe shapes. In this case the head loss is determined by the velocity and loss coefficients mainly. Because there are dramatical change of diameter and velocity, these become more affective factors. And it can be occurred that eddies make friction among fluids. So we should consider the loss coefficients. For example, if the sudden expansion is occurred, the mean velocity becomes slow down in a moment and pressure of pipe is dropped. In contrast the sudden contraction is occurred, the mean velocity becomes fast up in a moment and pressure of pipe increase.
In contrast to these theory, Our experiment results have some errors. There are some reasons of errors.
① As you can see the error marked by red circle in our result, there are regions of reverse proportion between diameter and velocity. We couldn't gauge the flow rate accurately because it is hard to measure the time by using a stop watch. So maybe gaged velocity has many errors comparison to real velocity.
② There can be air bubble in fluid flow. We eliminated the bubble before every trial, but the gap of connection site could be existed, so the air may flow into the pipe.
③ To apply the Bernoulli's equation, many assumptions are necessary. One of them is the steady flow. Steady flow shouldn't be changed by the time variable. But In my opinion there are velocity changes between inlet and exit. And there are frictions in fact. So the Bernoulli's equation can't be applied strictly in real conditions.
④ The environment condition wasn't constant. We calculate the viscosity and density of fluid at 17℃. But the laboratory temperature was not exact and also can be changed temporarily. If then the viscosity and density wasn't constant.
⑤ The length of pipe can affect the result. If the length of pipe is too long, the friction effect becomes larger. And we measured the p the resin short distance at experiment of straight pipe. In fact there was difference between short distance and long distance. So we choose the short distance results to reduce the effect of friction.
⑥ We failed to measure the pressure drop in elbow. I think that the flow rate was so slow that fluid was laminar flow, so it is possible that head loss gap isn't clear. Because the K factor is too small. So if we increased the flow rate quickly when we experienced the elbow, maybe we could get a apparent differences between manometer gauge. I missed that we didn't try this method.
8. Reference
- Fluid Mechanics for Chemical Engineers, p56~123 Second edition, by James O.Wilkes
- Chemical Engineering Laboratory Ⅱ, p13~16 SungKyunKwan Univ. chemical Engineering.
- Unit operation of Chemical Engineering, p121~123, McCabe, smith, Harriot

키워드

관 부속품,   압력 강하,   pipe accessory,   pressure drop,   pipe accessories,   압력강하 측정,   관부속품,   measurement