Lab 3:Bernoulli’s Theorem
I. Purpose:
In this lab we will apply the Bernoulli
Theorem to the flow of water through a tapering circular pipe (a venturi
meter).We will investigate how energy is conserved from one point to another in
some types offlow and how energy is
dissipated (that is, not conserved) in other conditions.
2.Turn on the feed water and carefully fill the manometer tubes with water to discharge all pockets of air from the system and ensure all connecting pipes are free from air.
3.Carefully adjusting the inlet feed and the flow control valve to establish the combination of flow rate and system pressure that will give the largest convenient difference between the highest and lowest manometer levels.
4.Record the scale reading of each manometer level into the Column (5) (Pressure Head).
5.Take three sets of readings of volume and time of water to find the flow rate using the volumetric tank. And find the average flow rate.
6.Insert the probe at the end of the parallel position of the duct, and then move it into the tapered portion 1cm at a time. Record its manometer scale reading in Column 7 (Stagnation Pressure Head).
Items |
First Trial |
Second Trial |
Third Trial |
Volume collected: |
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Time interval: |
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Flow Rate: |
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Average Flow Rate:Qavg = __________
Venturi Meter Reading and Calculation:
Tube |
(mm) |
V=Q/A (mm/s) |
V2/2g (mm) |
h=p/g (mm) |
Head V2/2g+h (mm) |
Pres
Head Hstag (mm) |
Hcalc-Hstag |
original total
head |
A |
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100% |
B |
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C |
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D |
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E throat |
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F |
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2.Comment on the validity of Bernoulli’s equation for the system tested on the different flow sections (convergent vs divergent).