EXPERIMENT 2: FLOW THROUGH VENTURE TUBE AND ORIFICE PLATE

TITLE

Experiment 2: Flow through Venture Tube and Orifice Plate

INTRODUCTION

A venturi tube is a tube with a constricted throat that increases velocity and decrease pressure. They are used for measuring the flow rate of compressible and incompressible fluid in pipelines. Orifice plate is a device which measures the rate of fluid flow. It uses the same principle as Venturi tube, namely Bernoulli’s principle which says that there is a relationship between the pressure of the fluid and velocity of the fluid. When the velocity increases, the pressure decreases and vice versa. Orifice plate usually placed in the pipe which fluid flows. As fluid flows through the pipe, it has a certain velocity and a certain pressure, with the hole in the middle, the fluid is forced to converge to go through the small hole, the point of maximum convergence actually occurs shortly downstream of the physical orifice.

OBJECTIVE

1. To determine the coefficient of discharge of Venturi tube,

EXPERIMENTAL PROCEDURES

Venturi and Orifice Meter Specifications

1. Venturi tube:

a. Inlet diameter,

b. Throat diameter,

2. Orifice plate:

a. Inlet diameter,

b. Throat diameter,

Part A: Flow through Venturi Tube

1. Inlet and throat diameter of the Venturi tube were recorded.

2. The Venturi tube was fixed into section F as shown in Figure 1.

3. All valves were closed except those that will let the water flows from the tank to section Venturi tube and return back to the tank. The direction of flow in the pipe was verified.

4. The manometer hoses were connected to the pressure tapping points of the Venturi tube.

5. The pump was switched on. Air bubble was removed from the apparatus.

6. The valve was adjusted on the left side of the Venturi tube to a certain position.

7. The valve of and were measured and recorded.

8. The actual value of flow rate, was measured and recorded.

9. Steps 8 to 8 for 5values of were repeated.

Part B: Flow through Orifice plate

1. Inlet and throat diameters of the Orifice plate were recorded.

2. The Orifice plate was fixed into section F as shown in Figure 1.

3. All valves were closed except those that will let the water flows from the tank to the section Orifice plate and return bank to the tank. The direction of flow in the pipe was verified.

4. The manometer hoses were connected to the pressure tapping points of the Orifice plate.

5. The pump was switched on. Air bubble was removes from the apparatus.

6. The valve was adjusted on the left side of the Orifice plate to a certain position.

7. The valve of and were measured and recorded.

8. The valve of and were measured and recorded.

9. The actual value of flow rate, was measured and recorded.

DATA AND CALCULATION:

Part A: Flow through Venturi Tube

Inlet inside diameter:

Inlet cross-sectional area:

Throat inside diameter:

Throat cross-sectional area:

Area ratio:

Gravitational acceleration:

g = 9.81m

(a)

(b)

(a)/(b)

( c )

(d)

equation 4

equation1

Measurement

No.

Volume measured

Time observed

Qactual

h1

h2

h1-h2

Qtheoretical

(litres)

(s)

(litres/s)

(m3/s)

(mm)

(mm)

(mm)

(m)

(m3/s)

1

5

25.10

0.1992

0.00020

400

325

75

0.075

0.00019

2

5

15.41

0.3245

0.00032

500

255

245

0.245

0.00035

3

5

11.88

0.4209

0.00042

600

180

420

0.420

0.00046

4

5

10.04

0.4980

0.00050

700

95

605

0.605

0.00065

5

5

8.25

0.6061

0.00061

800

20

780

0.780

0.00062


Part 2: Flow through Orifice Plate

Inlet inside diameter:

0.0185m

Inlet cross-sectional area:

Throat inside diameter:

Throat cross-sectional area:

Area ratio:

Gravitational acceleration:

g = 9.81 m

(a)

(b)

(a)/(b)

( c )

(d)

equation

equation 1

Measurement

No

Volume measured

Time observed

Qactual

h1

h2

h1-h2

Qtheoretical

(litres)

(s)

litres/s

(m3/s)

(mm)

(mm)

(mm)

(m)

(m3/s)

1

5

32.75

0.15267

0.00015

510

481

29

0.029

0.00014

2

5

14.75

0.33898

0.00034

585

440

145

0.145

0.00032

3

5

10.37

0.48216

0.00048

660

391

269

0.269

0.00043

4

5

9.03

0.55371

0.00055

735

350

385

0.385

0.00052

5

5

7.97

0.62735

0.00063

810

301

509

0.509

0.00059

CONCLUSION

As a conclusion, the experiment that have been carried out were successful, even though the data collected are a little bit difference compared to the theoretical value. The difference between the theoretical value and the actual value may mainly due to human and servicing factors such as parallax error. This error occur during observer captured the value of the water level, and . Besides that, it also may because there is bubble inside the pipe line. This is because the bubble was not properly flushed during bleeding. There is no other relative motion between the fluid particles. There is only stress that will be a normal stress which is equal to the pressure. There are a lot of possibilities for the experiment will having an error. Therefore, the recommendation to overcome the error is ensure that the position of the observer’s eye must be 90° perpendicular to the reading. Other than that, ensure that the bubble was fully removed from the pipe line.

REFERENCE

1. http://www.cee.mtu.edu/~dwatkins/ce3600_labs/venturi.pdf

2. http://intro2u.net/flowmeter/orifice-meter.htm

3. http://www.roymech.co.uk/Related/Fluids/Fluids_Or_No_Ven.html#venturi

5. Fluid Mechanics Fundamentals and Applications, Yunus A.Cengel and John M.Cimbala

4 Response to "EXPERIMENT 2: FLOW THROUGH VENTURE TUBE AND ORIFICE PLATE"

  1. Anonymous Says:
    January 16, 2011 at 6:59 AM

    wehy thanx au...haha..

  2. mekygearhead says:
    January 23, 2011 at 6:54 AM

    mtak share ye..peace

  3. Anonymous Says:
    August 10, 2011 at 10:31 PM

    thank my dear

  4. Anonymous Says:
    November 4, 2012 at 1:42 AM

    mntx share... tq

Post a Comment