Basic Measurement1

7/30/2019 Basic Measurement1

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Rene Zamarripa

Basic Measurements4/9- 4/16

4/23/2012

Thermo-Fluid Lab MECH 3313

Dr. Norman Love


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For the pressure gauge the objectives are to practice calibration of a

measurement device and to practice calculating experimental uncertainty. For the

viscosity, the objective is to be familiar with experimental methods of viscosity

measurment and to study the effect of temperature on viscosity variation. For

temperature, the objectives were to construct and use thermocouples and to

measure temperature on the surface of a flat plate.


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Table of Contents:

Introduction.. 7

Background Theory.7-8

Experimental Apparatus..9

Experimental Procedure11

Data Presentation12

Discussion.. 17

Discuss and conclude.12-14

Results.. 18

Conclusion19

Recommendations.2 0

References..2 1

Appendices22


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Nomenclature

-viscosity

F-Force

cp-Viscosity Values

A-area

x-mean value

xi-sum of measurements

sx-standard deviation

-uncertainty


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List of figure:

Figure 1-1-Pressure Gauge

Figure 1-Pressure gauge apparatus

Figure 2-Viscosity Apparatus

Figure 3-Temperature apparatus

Figure 4-calibration curve.

Figure 5-viscosity versus temperature

Figure 6- temperature versus time

Figure 7-temperature versus time with hot plate.


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List of tables

Table 1- pressure gauge including all of the 5 pressures.

Table 2- oil numbers along with the rpm and the viscosity values.


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Introduction

Pressure Gauge

In the experiment we used a Bourdon tube gauge. The Bourdon pressure gauge

uses the principle that a flattened tube tends to change to be straightened or

larger circular cross-section when pressurized. Bourdon tubes measure gauge

pressure, relative to ambient atmospheric pressure, as opposed to absolute

pressure; vacuum is sensed as a reverse motion. We also used a dead weight

tester. A dead weight tester apparatus uses known traceable weights to apply

pressure to a fluid for checking the accuracy of readings from a pressure gauge. A

dead weight tester (DWT) is a calibration standard method that uses a piston

cylinder on which a load is placed to make equilibrium with an applied pressure

underneath the piston. Deadweight testers take the pressure measured by a

deadweight tester is defined through other quantities: length, mass and time.

Typically deadweight testers are used in calibration laboratories to calibrate

pressure transfer standards like electronic pressure measuring devices.

Figure 1-1

Viscosity

Viscosity is a measure of the resistance of a fluid which is being deformed by

either shear or tensile stress. In everyday terms (and for fluids only), viscosity is

"thickness" or "internal friction". Thus, water is "thin", having a lower viscosity,

while honey is "thick", having a higher viscosity. Put simply, the less viscous the

fluid is, the greater its ease of movement (fluidity).


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The applied force is proportional to the area and velocity gradient in the fluid:

Absolute Viscosity

Temperature

Temperature is a physical property of matter that quantitatively expresses the

common notions of hot and cold. Objects of low temperature are cold, while

various degrees of higher temperatures are referred to as warm or hot. Heat

spontaneously flows from bodies of a higher temperature to bodies of lower

temperature; at a rate that increases with the temperature difference and the

thermal conductivity. In this experiment we used T-Type thermocouple wires

which were red and blue. The red wire had the conducting metal of Constantan

and blue had copper. These wires can withstand temperatures between -200 to

300 Celsius.A thermocouple is a device consisting of two different conductors

(usually metal alloys) that produce a voltage, proportional to a temperature

difference, between either ends of the two conductors. We use the voltage of theatmosphere to calculate the temperature.


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Figure 1

Figure 2

Figure 3
http://meter.com.my/datalogger/software_clip_image002.gifhttp://meter.com.my/datalogger/software_clip_image002.gifhttp://meter.com.my/datalogger/software_clip_image002.gif


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Apparatus

Pressure Gauge

Bourdon-Tube gauge

Dead weight tester

Weights

Viscosity

Rotary Viscometer

Thermometer

1000 ml beaker

Hot plate

Stand

Temperature

T-Type thermocouple wires

Thermocouple welder

Thermometer Hot plate

Pc data acquisition system


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Pressure gauge:

1. First, we set up the dead weight making sure the valve on the side was fully

closed.

2. Then we made our baseline reading which was the resting place of the gauge inwhich there was no pressure exerted.

3. Then we placed a weight on top and gave it a few pumps on the lever until the

weight slightly rose.

4. Then we took down the pressure at which it was at

5. We did these steps 5 with the same weight and repeated more times with

different weights

Viscosity1. First we set up oil 1 under the rotary viscometer

2. Then selected an rpm and gathered its viscosity value.

3. We did this for 3 different rpm settings

4. Then we proceeded to turn on the hot plate and took down the

temperature of the oil at room temperature for a desired rpm.

5. Then we took 5 temperatures randomly along with the viscosity value.

6. After we took the temperatures, we change the oil to the next one and

placed it under the viscometer.

7. We then proceeded to gather its viscosity value for 3 different rpm settings.

8. Then we turned on the hot plate one last time and took the temperature

ever increments of 5 degrees Fahrenheit along with the viscosity value

Temperature

1. First we cut a thermocouple wire and shaved off the ends to expose thewire.

2. Using the thermocouple welder, we made a butt-joint at one end of the

thermocouple wire.


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3. Then we connected the wire into data acquisition software and we each

took room temperature every one of us taking 30 seconds longer than the

last.

4. Then we turned on the hot plate

5. We used the last thermocouple which was connected to the software and

took the temperature readings

6. As soon as the temperature on the software would become constant, we

would take the time and increase the temperature on the hotplate

7. We did this for 3 different temperatures


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Pressure Gauge

Table 1

L40 L50 L60 L70 L80

430 PSI 439 PSI 441 PSI 458 PSI 462 PSI431 PSI 440 PSI 441 PSI 458 PSI 462 PSI

431 PSI 440 PSI 441 PSI 459 PSI 462 PSI



Discuss and Conclude

1. Pressure is being calibrated in this case because of the piston it has in the

tester. As more pressure in the fluid increases, the weight slowly rises, thus

creating the pressure reading.

2

figure 4

4 The deviation between the actual and measured values is rather high. This is

due to the calibration of the gauge which at normal pressure was 400.

410

420

430

440

450

460

470

40 50 60 70 80

Measuredvalue

True Value

Calibration Curve

L40

L50

L60

L70

L80


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Viscosity

Table 2

Oil 1

SPEED

20

RPM

30

RPM

50

RPM

OIL 2

SPEED

12

RPM

20

RPM

30

RPM

CP 101.1 106.4 109.7 CP 116 122.7 127.4

30

RPM

TEMP

F

CP 30

RPM

TEMP

F

CP

75 106.4 75 130

78 86 80 125.6

82 78.4 85 124

84 70.4 90 95

90 61.2 95 75.6

Figure 5

0

20

40

60

80

100

120

140

75 80 85 90 95

V

iscosity

Temperature in F

Viscosity vs Temp

Viscosity oil 1

Viscosity Oil 2


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Temperature

Figure 6

Figure 4

Figure 7

Discuss and conclude

2. It takes 1:48 for the first setting and 4:14 for the second and 4:50 for the last.

This was because the temperature of the hot plate was not yet hot enough.

22.2

22.4

22.6

22.8

23

23.2

23.4

23.6

23.8

24

143

85

127

169

211

253

295

337

379

421

463

505

547

589

631

673

715

757

TemperatureinC

Time

Temerature vs Time

Test 1

Test 2

Test 3

Test 4

0

20

40

60

80

100

120

140

160

180

198

195

292

389

486

583

680

777

874

971

1068

1165

1262

1359

1456

1553

1650

1747

Temp

Time

Temp vs time with hot plate

Test 1

Test 2

Test 3


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In table 1, we have all of the data acquired for the pressure gauge including all of

the 5 pressures.

In table 2, we have all of the data including the oil numbers along with the rpm

and the viscosity values.

In figure 4 its the calibration curve.

In figure 5 it is the viscosity versus temperature in the viscosity lab

In figure 6 it is temperature versus time in the temperature lab

In figure 7 its the temperature versus time but with the hot plate on.


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Pressure gauge Discussion:

The data we got for the pressure gauge experiment was in accordance to the

procedure because as we put the dead weights on the tester and pumped the

lever to increase the pressure, we would slowly levitate the weight and thepressure would be recorded on the gauge. But since the gauge was not calibrated

perfectly at zero, we had to start the experiment and calibrate it at 400 psi. This

however did not change the experiment outcomes; we could still get the actual

measurement of these weights by subtracting the 400.

Viscosity Discussion:

The data that we acquired for this experiment was according to the procedure

because as the rotary viscometer would begin to spin at a certain rpm with oil 1,

the viscosity values would begin to show on the screen. This however would vary

as we would increase the rpm of the viscometer, steadily increasing the values. As

we changed the oils to oil 2, we automatically began to see the changes in the

viscosity because the rpm was at low revolutions and the value of viscosity was

rather higher than the oil 1.

Temperature.

The data that we acquired for this experiment was according to the procedure

because as we would connect the thermocouples that we welded together into

the data acquisition software, the temperature of the surrounding air would show

up on the data acquisition program. As we would wait several seconds holding the

thermocouple in the empty space, the temperature would fluctuate, thus not

being very accurate. So we then took turns connecting our own thermocouples

into the software and increasing the time we would hold it by 30 seconds, we

would began to get more accurate as the time would go on.


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Pressure gauge

In table #1, we can see all the major data that was collected from the

experiment, including, the dead weight and the pressures we got with our

calibrated gauge. Since the gauge was not at zero, we calibrated it to 400 andthen just subtract the 400 by the calibrated results and compare them to the

dead weights results. In figure 4, the calibration curve, we can see the different

pressures compared to the dead weight pressure. As the dead weights pressure

rose by 10, the calibrated pressure rose, but not at a steady increasing rate.

Viscosity:

In table #2, we can see all the major data that was collected from the experiment,

including the rpm settings in both oil 1 and 2, the temperatures and the viscosity

values. We saw that in oil 1 the rpm setting would be slightly higher than that of

oil 2 meaning that the viscosity of the oil 2 was greater. Then as we would turn on

the hot plate and stir the oils, we would see that the viscosity values would

sharply decrease. This occurred in both oils as seen in figure 5. Both oils were put

to the hot plate experiment and as the graph show that oil 2 temperature would

increase, viscosity sharply drops almost constantly. To maintain the constant

pressure throughout the oil we had to stir.

Temperature

In figures 6 we can see just how accurately our data can be with more time. As

the thermocouple was exposed in increasing time intervals of 30 seconds more

each time, the temperature would become a more accurate reading. The

thermocouple that was held for 2 minutes got the most accurate results as

shown. In figure 7 we have the graph of the 3 different hot plat settings recorded

until they reached steady state. We can see that the second setting took a long

time. An educated guess would be that the hot plate was the culprit becauseitselectrical and takes a long time to heat up the plate.


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Pressure Gauge:

The main results we got in the pressure gauge experiment was closely related to

the theory because as the fluid would get compressed in the piston, there was

just enough pressure to lift the dead weight just enough to keep it suspended inthe air. We would read the results in the Bourdon-Tube gauge. But since the

gauge wasnt functioning properly, we had to calibrate it at 400 which was theoriginal place the needle was at resting place. The deviation between the actual

and measured values was rather large because of the calibration of the gauge.

Viscosity:

The results that we got clearly resembled what lies in the theory of viscosity.Meaning that when the viscometer would began to spin with a certain rpm, the

force that the viscometer puts out to create those rpm is the viscosity value. This

value differs between rpm. For example in oil 1 the viscosity values were between

100 at 20 rpm. However in oil 2 for 20 rpm the viscosity values were around 120

meaning that the more viscous of the two oils was oil 2. But as we began to

increase and add heat to the oils, the viscosity of the oils began to decrease

meaning that as the oil heats up the viscosity decreases.

Temperature

The results that we obtained in the temperature experiment helped us to

construct thermocouples and measure temperature with them. This clearly

resembles the underlying theory. As the thermocouple sits for a long time at

steady temperature, the results are more accurate than a thermocouple that sits

for 30 seconds. This same theory applies to thermometers because we need to

leave the thermometer at the temperature we want to measure as to getaccurate results. But as we began applying heat to the thermocouple the time

interval between that moment and steady state would take several moments,

because of the electric hot plate that takes its time to accomplish the desired heat

setting.


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Recommendation

Pressure gauge

A recommendation for the pressure gauge would be to have computerized

software that accurately measures the pressure.

Viscosity

A recommendation for the viscosity experiment would be for the viscometer to

give steady cp results.

Temperature

A recommendation for the temperature experiment would be for the software to

have an immediate reading of the temperature instead of waiting for steady

state.


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References

1) fluidengineering.co.nr/Manometer.htm

2) http://www.omega.com/literature/transactions/volume3/pressure3.html

3)J. P. Holman Heat Transfer, McGraw-Hill, 2002.

4) "Thermocouple temperature sensors". Temperatures.com. Retrieved 2007-11-04.

5) Kondepudi, D. (2008). Introduction to Modern Thermodynamics, Wiley, Chichester, Section32. pages 106-108.


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Appendices

Uncertainty analysis

Pressure Gauge

Xi

sx

=30.684.94 =39.6109.9 =41.4114 =58.2161.5 =62.4173.2

Viscosity

Oil 1 Oil 2

xi

402.4 550.2

x

80.48 110.04

sx

160.96 220.08

223.41248 305.471

=80.48223.41 =110.04305.474

153 198 207 291 312

30.6 39.6 41.4 58.2 62.4

61.2 79.2 82.8 116.4 124.8

84.9456 109.9296 114.9264 161.5632 173.2224

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Basic Measurement1