CE3502 lab2-1

# CE3502 lab2-1 - PRESSURE VELOCITY MEASUREMENT Laboratory...

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Laboratory section: 004 Name: Fahad Al Jaberi TA: Feng Wan Date of experiment: 09/17/08 (I did this work myself) Purpose: The objective of this laboratory exercise is to measuring the pressure at a point in a flow field and to demonstrate hoe the velocity profile in a flow can be measured and used to determine volumetric discharge. In this lab, we will perform the experiment using stagnation tubes in an air stream flowing through a pipe. A two-inch diameter pipe has been fitted with a rake of stagnation tubes and a static pressure tap on the pipe wall. These are connected to manometer bank filled wit colored water. These measurements, however, are the most common engineering fluid mechanics problems and the instruments are commonly used and we will encounter them in the future. Apparatus and procedure: 1- First, we will work with the Stagnation Tube Rake: we set the voltage at 60 V and turn the flow on. Then, record the static pressure in (cm) and the pressure for in the tubes that have different radiuses in (cm). There are two tubes that have the same radius, so we have to take the average of the two tubes with the same radiuses. Then we get ∆h=h static h average . We then calculate the local velocity using an equation derived from Bernoulli’s equation which is . After that, we plot u vs. r where r is the radius of the tube and also plot u vs. r 2 . To find the volumetric flow rate Q by getting the area under the curve u(r)

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vs. r and multiplying the area by (pi). Finally, we calculate the mean velocity of flow in the cross section V mean =Q/A. 2- Second, we use the Venturi Meter. We read the static pressure at two points in (mm) and we calculate the height difference ∆h and determine the flow rate using the equation given in lab. Q=2.0786 in (L/s) and convert our value to (m 3 /s). Moreover, we take the reading for the flow rates in the Hasting Meter Q (m 3 /min) and convert our reading to (m 3 /s). We then, calculate 3- We repeat step one and two using a voltage of 80V and 100V. Tabulation of computed results: For 60V ∆h(m) u(m/s) 0.0175 16.87791783 0.018 17.11733287 0.017 16.63505743 0.0165 16.38859851 0.016 16.1383762 0.01475 15.49515247 0.013 14.54693572 0.0125 14.26444406 0.011 13.38123465 0.09 12.10378215 Mean velocity=18.201(m/s), K=1.0587 For 80V ∆h(m) u(m/s) 0.027 20.96436565 0.0265 20.76934406 0.025 20.17297025 0.024 19.76539349 0.0235 19.55842031
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## This note was uploaded on 11/10/2011 for the course CE 3502 taught by Professor Hill during the Spring '08 term at Minnesota.

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CE3502 lab2-1 - PRESSURE VELOCITY MEASUREMENT Laboratory...

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