Forced Convection Full-Technical Lab Report

Full Technical Report: Experiment 6: Forced Convection

Name: Alfonso Figueroa_______________________________ Lab Team F4_________

1. Self Evaluated: Assessment Symbol/Color λ Date 4/24/15_________

2. Instr/Grader Evaluated by Assessment Symbol/Color Date _______________

3. Instr/Grader Evaluated by Assessment Symbol/Color Date _______________

Yes No Self-Regulation Issues (to be completed by Instructor/Grader)A. The electronic report was submitted on time

B. The front pages of the submission was this checklist with all Features self-assessed

Required ItemsYes No Checklist Item

λ 1. The work meets all expectations of Assignment_formatting.doc

λ 2. There is Pre-Reflection and a Post- Reflection written in the first person.

λ 3. The work is professional and ethical

λ 4. All quoted and non-original work is cited in a references section

λ 5. Work is free of mathematical errors (arithmetic, algebra, calculus, etc.)

6. All required elements of a full technical report are present.

λ a. There is a title page with complete abstract

λ b. There is an accurate table of contents and accurate lists of tables and figures

λ c. There is an introduction / theory / background section

λ d. There is a materials and apparatus / procedure section that discusses safety concerns for this experiment

λ e. There is a results section

λ f. There is a discussion / conclusions / recommendations section

λ g. There is a references section, appropriately (ACS Style) and consistently formatted

λ h. There is an Appendix containing the raw experimental data

Comments on the quality of the expected features and/or how they might be improved

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Rating*0 - 5

Rated Items

5 7. Rate the quality of the abstract (succinct, contains a summary or results, has appropriate tone)It provides a good summary of the lab stating how values were gained, values were found, and error accounted for.

5 8. Rate the presentation and content quality of the introduction/theory/background section(s) (relevant specific objectives clearly stated, experiment clearly motivated, importance, brief outline of approach, explicit purpose and scope of report, succinct but sufficient and relevant theory)

Gives a great background about forced convection and how it is applied in industry and to different materials.

5 9. Rate the quality of the apparatus/procedure section (Concise, hardware and software described, appropriate technically drawn figures, Safety issues addressed, enough detail in procedure to allow reproduction of results)

There is a detailed apparatus that helps in showing how the experiment is performed. The procedures are in a format where it can be replicated by anybody doing this lab for the first time.

5 10. Rate the quality of the results presentation (description of analyzed results, good use made of plots, tables, figures, that serve the author’s and audience’s purpose, including all significant findings)Numerous graphs were plotted which include raw data, error bars, rearranged lumped capacity method, and Heisler method.

5 11. Rate the quality of the technical analysis (clarity and depth of presentation, sophistication of analytical analysis, correctness of ‘error analysis’, sufficiency of theory utilized, explicit integration of concepts from earlier coursework)

All the graphs ended up being analyzed effectively throughout the discussion given theories behind the trends in in graphs and for any possible errors.

5 12. Rate the quality of the discussion / conclusions / recommendations section (explanation of significant data, patterns, comparison with predictions, including plausible explanations for discrepancies, findings related to the problem and objectives from introduction, clear statement of what results do and do not demonstrate)

Summarizes the final thoughts based on the results section and introduction.



Rating*0 - 5

Rated Items

5 13. Rate the effectiveness of presentation (professional in look, tone, style, vocabulary; consistent use of terms, matched to audience, goals and purpose addressed throughout, implicit as well as explicit goals served, structure of paragraphs, sentences appropriate to audience, goals)

Everything is in perfect formatting based off of Burrow’s guideline and the paper was checked at the writing center for proper sentence structure and correct grammar.

5 14. Rate the quality of the Pre-reflection and Post-reflection (addresses issue as described in Assignment_reqs.doc)

There is a page of writing for each reflection stating what I truly felt.

Extra Credit* (each can add up to 0.15 to Rated item Average)

Yes Describe features of your work that you believe qualify for “Extra Credit”1.

2.

3.

* If you self-assess a rated item at 4 or 5, or claim Extra Credit, you MUST explain WHY, and ideally explain why using the reasons given in the Course’s Assessment/Grading document.

Results of Initial Assessment (to be completed by Instructor/Grader)If substantially incomplete (NC), grade is 0; if any requirements not met or average of Rated features less than 2.8,

grade is 50 (NI); otherwise, Grade = average of Rated Features + Extra Credit

E M NI NC

E, all Yes’s for Required Items, no Rated Items below 3, Rated Item average above 4.4M, all Yes’s for Required Items, Rated Item average at or above 2.8NI, any No’s for Required Items or Rated Item average below 2.8NC, there is little to no work to be assessed; Rated item average below 1.8


Alfonso FigueroaF4

4/24/15

Pre-ReflectionExperiment # 6: Forced Convection

Full technical laboratory/research report

For this upcoming lab starting on April 17, forced convection will be applied to objects under transient cooling for Professor Burrows. For this lab, the goals that are expected to be achieved are: to be able to work cooperatively with fellow team mates, to be reliable, and to be prepared for the lab. We plan on accomplishing these goals by meeting up before lab so that the team leader can go over the lab as a whole. We can then assign each other positions and roles that need to be taken before we even set foot in lab. Of course, lab safety is something we should all go over so that none of us come under harm’s way. With all this planned out, everything should go according to plan and our goals should be achieved.

With this lab being entirely about forced convection, the one concept that comes to mind that I need to know is heat transfer. With that in mind, I am hoping to touch up a bit on my heat transfer knowledge before lab so I can get a better idea of what I should be observing. Some key concepts that come to mind are forced convection, biot number, and understanding the lumped parameter model and its applications. With having this idea in mind during lab, I can have a better understanding of what is occurring throughout the experiment.

For this lab, I feel that I have a number of strengths that I can definitely offer throughout. One of them is that I am a very reliable team member and that if I am ever asked to do anything, I will not hesitate and get straight to it. Another strength that I can recall is that I am a good dial controller and offer very precise movements, so if this lab ever requires such movement, I know that I can be relied on to do the dialing. I do not believe I have any weaknesses from the looks of this lab. If anything comes up that gives me trouble, I will be sure to ask a fellow mate for help or a TA for assistance.

After this lab is over and all the data is gathered, I am hoping to bring out the best in my last full technical lab report. Just like the last lab report I completed, I expect to meet or surpass it which means I can hopefully end up with a high score in the 80s or 90s range. I plan to stay up late nights so I can get most of my research and formatting done. If I ever get stuck on any parts, I will ask a fellow team member and/or TA for assistance, just like I would in lab. If I follow through with all of this in mind, then I should be able to get through this lab report in about 3 days tops.

With all the work I plan to put into this report, I am expecting these skills to be applied to future tasks-- working for a company of my desire. Having the writing skills, hard work ethic, and most importantly, precise formatting skills will impress any employers and they will definitely want to have me around in the long run. After this lab, I expect to have a much better understanding of forced convection. If a company ever asks me about forced convection, I can show them the report I made on it.


Forced Convection

A Research Report Submitted by:Alfonso Figueroa

in partial fulfillment of the requirements ofCHE 352

Spring Semester, 2015Arizona State University

Chemical Engineering Program

AbstractForced convection is a process that is used in determining heat transfer coefficients of different types of materials. In lab, raw temperature data was collected for the temperature of two different cylindrical objects, which includes aluminum and concrete. The raw data was then plotted for where convection theories are determined based off the following line trends. The data is then plotted again in the form of the lumped capacity method so the heat transfer coefficient, h, can then be determined. The new value for h is determined to be correct by using the Biot number method. If the h value gained does not abide to the method, then the Heisler method is used to determine the h value. The h value found for aluminum would then come out at as 43.00 W /(m¿¿2∗K )¿ using the lumped capacity method. The h value gained for concrete ends up as 85.86W /(m2∗K ) using the Heisler method. Error that could have contributed to data could have been the thermocouple reader where there was ∓2 degrees output.

Forced Convection Alfonso FigueroaF4

4/24/15

Table of ContentsPage

Abstract.............................................................................................................................................iIntroduction and background ..........................................................................................................4Theory .............................................................................................................................................4Materials and Apparatus .................................................................................................................6Procedures .......................................................................................................................................6Safety ..............................................................................................................................................7Results .............................................................................................................................................7Discussion......................................................................................................................................12Conclusion.....................................................................................................................................13References......................................................................................................................................14Appendix A: (Sample of raw data for aluminum and concrete cylinders)....................................15

List of FiguresPage

Figure 1 (forced convection apparatus,(1)enclosed box,(2)styrofoam,(3)cylindrical object,(4)thermocouple,(5)small fan)........................................................................6Figure 2 (Plot of raw data for aluminum)........................................................................................7Figure 3 (Plot of raw data for aluminum with error bars)................................................................8Figure 4 (Plot of rearranged lumped capacity method for aluminum)............................................8Figure 5 (Plot of raw data for concrete)...........................................................................................9Figure 6 (Plot of raw data for concrete with error bars)................................................................10Figure 7 (Plot of rearranged lumped capacity method for concrete).............................................10Figure 8 (Plot of Heisler method for concrete)..............................................................................11

List of TablesPage

Table 1 (Sample of raw data for aluminum cylinder)....................................................................15Table 2 (Sample of raw data for concrete cylinder)......................................................................16

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List of Terms

Density (kg/m3)................................................................................................................................T (°C)..............................................................................................................................................THeat Transfer Coefficient (W /m2 K )…………..…………………………………………...……hSurface Area (m2)…………………………………………………………………………….…...AHeat Capacity (J /(kg K ))………………………………………………………...…..………......cp

Volume (m3)…………………………………………………………………………...………….VTime (s)……………………………………………………………………………………………tCharacteristic Dimension of the body (m).....................................................................................x1

Measurement of the center of the body (m).....................................................................................xThermal Conductivity (W/(m K))……………………………………………………………...….kX axis of Heisler Chart (dimensionless)..........................................................................................XY axis of Heisler Chart (dimensionless)..........................................................................................YThermal diffusivity (m2/s)…..…………………………………………………………………….αHeisler Chart Slope Number (dimensionless).................................................................................mHeisler Chart Slope Number Increments (dimensionless)...............................................................n

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Introduction & Background

Heat is a major contributor in industry which results from factories, foundries, and industrial plant facilities. All this heat is used for different applications which include drying, curing, casting, molding, and many more different processes. With these high increases in temperature, numerous equipments can be in jeopardy of malfunctioning and, thus, lead to the failure of the equipments. Once this happens, this can deter planned out operating schedules and negatively impact the business financially. To deal with all the heat that is produced from all these different processes, cooling is to be involved to help subsidize the effect.1

The heat produced comes from many different vital processes used in industry every day. It is used in food industry where industrial sized ovens bake bread or cook up other delectables. It is applied to chemicals which can include drying inks and dyes. It is also applied to materials, which is the main focus of this report. It can be applied to metals so that they can be welded, to rubber so it can accelerate the cross linking necessary to be cured, and to plastics so they can be molded for everyday use. To make sure these materials are being processed effectively, they must be cooled so they can continue down the assembly line.1

Theory

When cooling heated objects with a fluid, like air for instance, it is called forced convection. This means that the faster a fluid is travelling over an object, the faster it is capable of removing heat away, thus cooling the object. Because small materials are being used in this lab to test the theory of heat convection, a heat balance is created for the object.

(1)hA ( T f−T ) dt=c p ρV dT

This formula indicates that heat transfer of a fluid to an object must equal the change in internal energy of that object. On the left hand side of the equation, h is the heat-transfer coefficient, A is the surface area of the object, T is the temperature of the object at a certain time, and T f is the final temperature of the object. On the right hand side of the equation, c p is the heat capacity, ρ is the density, and V is the volume where all described variables correlate to the object. Equation (1) can then be integrated to form the Newtonian cooling method, or the notable, lumped capacity method.

(2)

T−T f

T0−T f=e

−( hAcp ρV )t

This formula is very convenient to use, but only if the object has a high thermal conductivity compared to the external surface resistance. For this lab, the formula will be plotted on a graph to

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determine the h value. To use this formula for a graph, first the natural log must be taken on both sides of equation (2).

(3)

ln (T−T f )=−( hAc p ρV ) t+ ln (T o−T f )

This can then be plotted as ln (T−T f ) vs. t on a graph where the slope, −(hA /c p ρV ), can be used to find the h value. A way to determine if the lumped capacity formula can be applied is if its Biot number is less than 0.1. The following equation comes out as so

(4)

NBi=h x1

k=

h ( VA )

k<0.1

k is the thermal conductivity of the object, x1=(V / A ) is the characteristic dimension of the body, and NBi is the dimensionless biot number. What the Biot number ends up comparing is the relative values of internal conduction resistance and surface convective resistance to heat transfer. If the Biot number ends up being greater than 0.1, that means that there was a large heat-transfer coefficient at the surface. If this happens, another more complex method has to be implemented-- the Heisler charts.

For a cylinder like shape, the dimensionless parameters used to determine unknown variables are as follows.

(5)

X=αtx1

2

(6)

Y=T1−TT 1−T 0

(7)

m= kh x1

(8)

n= xx1



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Equation (5) is used for the x-axis, (6) is used for the y-axis, (7) is used to determine the slope, and (8) is used to determine the increment of the slope. New variables that are introduced include α , which is the thermal diffusivity of the object, and x, which is the measurement of the center of the cylinder like object. Once the Biot number is calculated throughout the experiment, then the correct process needed to solve the problem will be chosen.2



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Materials and ApparatusFor this apparatus, there is an enclosed box that has two windows on the side for viewing purposes [1]. Inside, there is insulation in the center of the box which is made up of styrofoam [2]. A cylinder like object [3], taken right of an oven, is placed atop the styrofoam in the box where thermocouples are attach to the center and outer ridges of the cylinder [4]. There is a small fan on the outside of the box where it blows room temperature air into the box through a small opening [5]. Data is then collected and plotted on a provided computer via software.

Figure 1:forced convection apparatus3,(1)enclosed box,(2)styrofoam,(3)cylindrical object,(4)thermocouple,(5)small fan

Procedure

The first step of this lab is to preheat the oven to 150˚ - 160˚. Once the oven is at the determined level of temperature, place the cylindrical concreate object into the oven. While the concrete is heating up, start up the small fan that is attached to the enclosed box and a continuous stream of air starts to flow. Once the concrete is heated to its designated temperature, carefully remove the concrete and then place it upon the styrofoam, located in the center of the enclosed box. Attach thermocouple wiring to the center and the outer ridge of the concrete. Then record the initial temperature and surface temperature read off from the thermocouple. Now a computer program will record the temperature of the concrete at a designated time. Once the desired time is reached, redo all of the steps again, but now with an aluminum cylinder. Make sure to record the dimensions of the cylinders with calipers. Finally, turn off all electronic equipment which includes the small fan, the oven, and the computer.

Safety



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Make sure that proper clothing is being worn which includes short sleeved shirts, long pants, and lab goggles. Since this lab deals with moving extremely hot objects from one place to another, gloves must be worn when transporting the objects.

Results

The raw data is collected for aluminum which is then plotted on a temperature vs. time graph.

0 200 400 600 800 1000 1200 1400 1600280

290

300

310

320

330

340

350

surface center

Time (seconds)

Tem

pera

ture

(Kel

vin)

Figure 2: Plot of raw data for aluminum

Based on figure 2, the temperature is practically consistent on the surface and the center of the aluminum cylinder. It starts off around 345 K and then steadily slopes downward to 310 K in a time interval of 1500 seconds. A reason for such a phenomenon to occur can be having a high thermal conductivity or low internal conductive resistance.2

An error analysis is then performed on the raw data for aluminum with error bars.



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0 200 400 600 800 1000 1200 1400 1600280

290

300

310

320

330

340

350

surface center

Time (seconds)

Tem

pera

ture

(Kel

vin)

Figure 3: Plot of raw data for aluminum with error bars

The cause for error could have happened from a number of reasons, including stagnation of air within the box, plotting points incorrectly, and by misreading the thermocouple. Since the thermocouple reader is somewhat dated, it is bound to misread some of the temperatures. When observing the thermocouple reader, a 2∓ degree misreading was seen. The error bars are thus in a positive 2 degree form and negative 2 degree form.

The next plotted graph for aluminum is the temperature difference vs. time.

0 200 400 600 800 1000 1200 1400 16000

0.5

1

1.5

2

2.5

3

3.5

4

4.5

surface centerLinear (center)

Time (seconds)

ln(T

-Tf)

(dim

ensio

nles

s Kel

vin)

Figure 4: Plot of rearranged lumped capacity method for aluminum



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The following graph was created from modified lumped capacity equation (3), where the slope is used to calculate the h value. The slope gained from the graph ends up giving −0.001/ s, which is then used to find the h value of 43.00 W /(m¿¿2∗K )¿. This value seems reasonable, but must be determined true from the Biot equation. The Biot number then reads as 0.0037, which is less than 0.1. The h value founded for aluminum is in fact, correct. This makes sense, considering aluminum has a large thermal conductivity which was mentioned in regards to figure 1.

Now, we take a look at the raw data collected for concrete, which is then plotted on a temperature vs. time graph.

0 500 1000 1500 2000 2500 3000 3500270

280

290

300

310

320

330

340

350

360

surface center

Time (seconds)

Tem

pera

atur

e (K

elvi

n)

Figure 5: Plot of raw data for concrete

Looking at the graph, the surface temperature and center temperature have similar trends.The surface temperature line starts around 340 K, where it concaves downward until it hits 300 K at the 3000 second mark. The center temperature line begins around 345 K, where the line trends downward in a semi-straight form until it reaches 300 K at the 3000 second mark. The two lines converge at the end, where uniformity in temperature is then accomplished. Reasons for the lines not overlapping can be it has a low thermal conductivity or has a large heat-transfer coefficient.

An error analysis is to then performed on the raw data for concrete with error bars.



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0 500 1000 1500 2000 2500 3000 3500270

280

290

300

310

320

330

340

350

360

surface center

Time (seconds)

Tem

pera

atur

e (K

elvi

n)

Figure 6: Plot of raw data for concrete with error bars

Similar to the error analysis of aluminum, there are a number of factors that could cause the errors. The same possibilities apply when plotting points incorrectly, such as stagnation of air within the box, and through misreadings from the thermocouple. Considering the age of the thermocouple, misreadings are likely to occur. When observing the thermocouple readers output, a trend of ∓2 degrees is evident. Thus, the error bars are in a positive 2 degree form and negative 2 degree form.

The next graph for concrete that is plotted is the temperature difference vs. time.

0 500 1000 1500 2000 2500 3000 35000

0.5

1

1.5

2

2.5

3

3.5

4

4.5

surface Linear (surface)center Linear (center)

Time (seconds)

ln(T

-Tf)

(dim

ensio

nles

s Kel

vin)

Figure 7: Plot of rearranged lumped capacity method for concrete



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Since the trends of concrete showing opposite effects of aluminum were discussed, the Biot number may end up being greater than one. The slope ends up coming out with a value of −0.001/ s , which is the same number gained for aluminum. Although it is the same slope, the slope does not mean concrete has the same properties as aluminum. With the different properties of concrete, the h value is 34.20 W /(m¿¿2∗K )¿. This is smaller than the h value gained for aluminum, which contradicts what was said in figure 1 about the trends showing a larger h value. To see if this value is correct, the Biot number must be calculated. The Biot number results in 1.3, which is greater than 0.1. This means the h value gained from the lumped capacity method is incorrect and another method does not need to be used.

The new method used to determine the h value is the Heisler Method.

0 0.5 1 1.5 2 2.50

0.2

0.4

0.6

0.8

1

1.2

𝑋= /( 1^2 )𝛼𝑡 𝑥 (dimensionless)

𝑌=(1−

)/(

1−0

)𝑇𝑇

𝑇𝑇(d

imen

sionl

ess)

Figure 8: Plot of Heisler method for concrete

The Heisler method is based on using the dimensionless equations mentioned in the theory section. The line gained is a curved position, which determines the slope. The value of the slope ends up turning out to be -0.3065 which then can be used to find the h value. Equation (6) is then used to determine the h value which ends up coming up at a value of85.86 W /(m2∗K ). This is more reasonable compared to the last h value gained because the value is larger.



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Discussion

The raw data collected for aluminum showed overlapping lines for the center and outer temperatures. The temperature decreased in a slope like manner the longer the cylinder was left in the box. Reasons for the center and outer temperatures being the same can be accounted for a number of reasons. The solid has a high thermal conductivity and a low internal conductive resistance compared to the blowing wind, and/or the solid is very small. These theories are proven after the h value and Biot number are found.

Before finding the above stated values, error analysis was done on the raw data for aluminum. A number of reasons for errors to occur include stagnation of air within the box, incorrectly plotted points, and possible misreadings from the thermocouple. The highest possible error that could have occurred is the misreadings from the thermocouple. The thermocouple reader used is old and could cause some misreadings. When analyzed carefully, there was a showing of ∓2 degrees. In the long run, this did not cause any noticeable off putting plot points, meaning the data collected was precise.

To find out if the following theories hold up for aluminum, a modified version of the lumped capacity formula was plotted. Once plotted, the h value was found to be 43.00 W /(m¿¿2∗K )¿. This sounds reasonable so far, since the h value is at a small value. To make sure it was correct, the Biot number was calculated using the newly gained h value. The resulting Biot number was 0.0037, which is less than 0.1. Thus proving the new found h value is correct and theories predicted for aluminum are also correct.

Now moving on to concrete, the raw data plotted showed non overlapping lines for the outer and inner temperatures. The surface temperature showed a faster decrease in temperature compared to the center temperature. They both, however, end up converging with each other at around 300 K. Since these lines don’t overlap each other, that means there are a number of different theories that can explain why they are so separate as compared to aluminum. Reasons the lines are separated are concrete has a low thermal conductivity, a large heat-transfer coefficient, and/or the internal resistance is not small. The theories were tested using different methods, which include using the Biot number and the Heisler chart method.

Once again, before testing these theories, error analysis was performed on the raw data gained for concrete. The errors for concrete are the same as those for aluminum. Once more, the reasons include stagnation of air within the box, incorrectly plotted points, and by possible misinterpretations from the thermocouple. The most likely possible error occurred noticeably is the thermocouple. An old, warn out piece of equipment is bound to make an error. When analyzed in depth, it was found there was an off put reading of the temperature at around ∓2 degrees. In the end, the graphs were smooth with little to no displacements of the data points.

Now, to see if the theories hold up, the modified lumped capacity method was plotted using the concrete raw data values. The resulting h value from the slope of the graph was34.20W /(m¿¿2∗K )¿. This seemed odd, since the concrete ended up with a higher h value than the aluminum h value. To see if this was actually correct, the Biot number was then calculated with the newly gained h value. The Biot number gained had a 1.3 value. This is larger than 0.1, which means the h value gained was indeed, incorrect.



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This means another method, the Heisler method, had to be implemented to calculate the h value. Once the line was plotted, the slope was found and the h value was then capable of being found. The newly gained h value that was obtained resulted in a value of 85.86W /(m2∗K ). This is a more reasonable h value, since it is bigger in value compared to the previously calculated value.

Conclusion

Heat is a common phenomenon that occurs everywhere, especially in chemical engineering facilities as a whole. With all of the different applications that heat is involved in, it is obvious cooling is necessary. It is applied to numerous different materials, but the main points of focus are metal and polymer.1 The graphs gained gave an idea of what types of values were to be gained for the heat transfer coefficient, h. Two different methods, the Biot number and Heisler method, were used to calculate the h value. In the end, aluminum gained the correct h value from the Biot Number method, and concrete gained the correct h value for the Heisler method. These values helped in determining aluminum had a low heat transfer coefficient and concrete has a high heat transfer coefficient. Knowing the heat transfer coefficient for any type of material will help in determining how long it can take for a material to cool from the inside out.



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References

[1] industrialfansdirect. https://www.industrialfansdirect.com/wp/2013/10/fans-and-forced-convection-in-process-cooling/ (accessed April 21, 2015)

[2] Geankoplis, Christie John. Transport Processes and Separation Principles, 4th ed.; Pearson Education: Upper Saddle River, N.J, 2003. Print.

[3]spaceflight.http://www.spaceflight.esa.int/impress/text/education/Heat%20Transfer/Convection%2002.html (accessed April 22, 2015)



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Appendix A: Sample of raw data for aluminum and concrete cylinders

Table 1: Sample of raw data for aluminum cylinderTime

(s)Ambient Temp

(˚F)Surface Temp

(˚F)Center Temp

(˚F)0 73.45 163.09 162.725 73.5 163.28 162.9510 73.62 163.01 162.7815 73.67 162.56 162.3820 73.71 162.08 161.9225 73.78 161.65 161.530 73.82 161.21 161.0635 73.9 160.78 160.6440 73.94 160.36 160.2245 73.97 159.94 159.850 73.98 159.5 159.3755 73.99 159.07 158.9460 74 158.63 158.5165 74.03 158.2 158.1370 74.04 157.8 157.7475 74.06 157.39 157.380 74.06 156.97 156.8885 74.08 156.56 156.4590 74.1 156.15 156.0495 74.12 155.74 155.63100 74.13 155.34 155.22105 74.14 154.93 154.8110 74.15 154.51 154.39115 74.16 154.12 153.99120 74.15 153.72 153.58125 74.14 153.33 153.19130 74.15 152.94 152.8135 74.15 152.55 152.41140 74.15 152.14 152.01145 74.17 151.77 151.63150 74.18 151.39 151.24155 74.21 150.99 150.85160 74.24 150.61 150.48165 74.24 150.25 150.1170 74.24 149.87 149.72175 74.23 149.5 149.34



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Table 2: Sample of raw data for concrete cylinderTime

(s)Ambient Temp

(˚F)Surface Temp

(˚F)Center Temp

(˚F)0 72.79 155.91 163.645 72.93 155.14 163.6410 73.14 153.44 163.5915 73.28 151.8 163.5520 73.36 150.22 163.525 73.45 148.94 163.4630 73.49 147.77 163.4235 73.54 146.66 163.3940 73.56 145.68 163.3545 73.58 144.83 163.3250 73.63 143.89 163.2855 73.64 143.06 163.2360 73.65 142.28 163.1965 73.67 141.63 163.1370 73.67 140.89 163.0975 73.66 140.22 163.0280 73.64 139.49 162.9685 73.64 138.97 162.8990 73.62 138.39 162.8195 73.63 137.79 162.73100 73.62 137.15 162.64105 73.63 136.6 162.54110 73.62 136.15 162.41115 73.6 135.71 162.25120 73.61 135.27 162.11125 73.6 134.77 161.94130 73.62 134.26 161.77135 73.63 133.85 161.59140 73.62 133.43 161.38145 73.63 133.03 161.2150 73.65 132.62 161.01155 73.65 132.27 160.81160 73.63 131.88 160.57165 73.65 131.52 160.38170 73.66 131.09 160.17175 73.67 130.69 159.93



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Alfonso FigueroaF4

4/24/15

Post-ReflectionExperiment # 6: Forced Convection

Full technical laboratory/research report

This is my last full tech and last lab report overall. I am glad it has all finally come to an end after spending numerous late nights getting these reports done. From all the time spent on working on these lab reports, I gained a number of skills. First, formatting is something I am now used to and can be applied to any type of paper write. Further, I learned to manage my time efficiently to get the assignments done on time. Most importantly, my writing has, in my opinion, improved more since I started going to the writing center to get my papers checked.

When in lab, a number of different approaches were implemented. Meeting up before and discussing roles with my group before lab was a great approach, since we all knew what our duties were going into the lab. An approach that did not work was when my group attempted to figure out how to use the equipment before asking Fred or a TA. When working, I feel like I was an effective team mate, for I always did the tasks I was assigned and helped out my other mates if needed. Knowing what to improve on, it would be a better idea to just ask Fred or a TA to show how to operate the equipment instead of us trying to figure it out.

Strengths that came into play during this lab ended up being a great and reliable team mate. Whenever I was told to do a certain task, I never hesitate and I get straight to doing it. Sometimes I noticed other members having a hard time trying to figure something out where I would come and try to help in solving whatever issue it is that they are having. During lab, there was never a point where I had troubles with any tasks I was assigned. This was probably one of my most successful labs when it came down to showing my true strengths.

When doing this lab I felt that I learned a lot more about forced convection. Being able to apply concepts learned from Heat and Mass transfer into actual real life experiments gave me a much better understanding of the theories implemented. Being able to find the heat transfer coefficient for aluminum and concrete ended up giving different methods in solving for it. This concept is definitely going to be used in future chemical engineering classes since heat takes a big role overall. Knowing more about the heat properties of concrete, it is of no wonder why it is still hot, even at night since it takes a while for heat to travel up from the center of the concrete.

After finally completing this lab report, I feel that my interest in forced convection has raised my curiosity for it. Knowing that it involves materials, a great interest of mine, makes it even all the more desirable to learn more of. I would like to test other materials like ceramics, semiconductor, and composites. I would also like to get into more polymers as well which can include plastics, rubber, and food products. Why I chose food products is because I want to work in the food industry which heat transfer is a major factor in producing the delectables. With all the different concepts that are involved and how it applies to my future career choice, I am sure it will keep me interested in it for a long time.


Forced Convection Full-Technical Lab Report

Engineering

Transcript of Forced Convection Full-Technical Lab Report