Flow measurement lab report discussion

EGME-306B-06

Spring 2015

Engineering Report

EXPERIMENT #1

Flow Through A Venturi Meter

Using Water As The Working Fluid

(Ref. Experimental Data Group 02- Taken on Feb 6, 2015)

By

02/20/2015

TABLE OF CONTENTS

List of Symbols………...…………………………………………………………………………………………2

Abstract…………………………………………………………………………………………................3

Procedure………………………………………………………………………………………………….4

Theory……………………………………………………………………………………………………..5

Results……………………………………………………………………………………………………10

Sample Calculations………………………………………………………………………………………………18

Error Analysis…………………………………………………………………………………………………..22

Discussion………………………………………………………………………………………………..26

References………………………………………………………………………………………………..28

LIST OF SYMBOLS

………………………………………………………………………………………..Mass flow rate ()

……………………………………………………………………………………………..flow rate ()

………………………………………………………………………………………...Mass density ()

……………………………………………………………………………………………...…gravity ()

……………………………………………………………………………………..…inlet pressure ()

………………………………………………………………………………………….inlet velocity ()

…………………………………………………………………………………………...inlet area ()

………………………………………………………………...inlet throat height from datum point ()

………………………………………………………………………………………outlet pressure ()

………………………………………………………………………………………...outlet velocity ()

………………………………………………………………………………………….outlet area ()

……………………………………………………………….outlet throat height from datum point ()

C…………………………………………………….………………discharge coefficient (dimensionless)

c………………………………………………………………………………………...speed of sound ()

Re……………………………………………………………………...Reynold’s number (dimensionless)

M…………………………………………………………………………...Mach number (dimensionless)

ABSTRACT

The motivation of this laboratory experiment is to analyze the flow of a fluid passing through a Venturi meter. The scheme is to compare the experimental volumetric flow rate to the theoretical volumetric flow rate. Deriving the Venturi velocity formula from the Bernoulli and continuity equations attains the theoretical volumetric flow rate.

It was found that the assumption of a frictionless surface through the Venturi meter was incorrect. When the water flows there is a head loss, which causes dissipation of energy throughout the system. Other factors such as human error, air bubbles in the fluid, and calculation round-offs led to discrepancies in the data.

RESULTS SUMMARY

Table 1: Pressure in piezometer tube and distance the fluid elevated to in Venturi meter

Venturi data and Piezometer Station

Piezo tube H2O height at station X , hX in.± .1in.

Distance from end, X in.

Venturi diameter D in. at X

Piezo. Station

Run 1

Run 2

Run 3

Run 4

Run 5

Run 6

hA-hD≈10 inH20

hA-hD≈8 inH20

hA-hD≈6 inH20

hA-hD≈4 inH20

hA-hD≈2 inH20

hA-hD≈.6 inH20

0

1

A-

9.3

8.8

8.0

7.0

6.1

5.5

1.125

1

A

9.3

8.8

8.0

7.0

6.1

5.5

1.625

1

A+

9.3

8.8

8.0

7.0

6.1

5.5

1.875

0.906

B

8.9

8.3

7.7

6.9

6.0

5.4

2.375

0.719

C

5.4

5.3

5.4

5.3

5.3

5.2

2.625

0.6445

D-

0.2

0.8

1.9

3.0

4.1

4.9

2.9375

0.6445

D

0.2

0.8

1.9

3.0

4.1

4.9

3.25

0.6445

D+

0.2

0.8

1.9

3.0

4.1

4.9

3.5

0.652

E

0.7

1.2

2.2

3.1

4.2

4.9

3.875

0.705

F

3.4

3.6

3.9

4.3

4.7

5.0

4.5

0.759

G

4.9

4.9

5.0

5.1

5.1

5.1

5

0.813

H

5.9

5.9

5.6

5.5

5.3

5.2

5.5

0.866

K

6.7

6.4

6.1

5.8

5.5

5.5

6

0.92

L

7.1

6.9

6.5

6.0

5.6

5.3

6.75

1

M-

7.8

7.4

6.9

6.3

5.7

5.3

6.875

1

M

7.8

7.4

6.9

6.3

5.7

5.3

7.875

1

M+

7.8

7.4

6.9

6.3

5.7

5.3

Graph 1: Piezometer tube versus distance of fluid in Venturi meter

Graph 2: Volume flow rate versus the square root of the height difference

Graph 3: Ideal Volume Flow Rate versus Discharge Coefficient

Graph 4: Free Stream and Throat velocity versus actual volume flow rate

Graph 5: Free stream and throat Mach number versus actual volume flow rate