Oh!
(What the?)
(What the)
You're so unbelievable!

("Unbelievable," by EMF, 1990)

 

THE PTOA HEAT TRANSFER FOCUS STUDY CONCLUDES

PTOA Readers and Students ... WAY TO GO AGAIN!

THUMBS WAY UP!

You have read each PTOA Heat Transfer Focus Study Area Segment in the intended sequential order and now expertly understand how the Process Variable Temperature is changed by heat transfer in the process industries.

Before you began the PTOA Heat Transfer Focus Study, your understanding of how the principles of heat transfer are harnessed to manage the Process Variable Temperature matched Fred's understanding of the subject.

 

Now PTOA Readers and Students are such experts in temperature and heat transfer that they completely understand how irritating the fairy tale of "Goldilocks and the Three Bears" is regarding the inane use of heat transfer.

A family of bears living and behaving like humans in their totally  humanlike home is highly unlikely.

Wanting the Reader to root for a stupid girl after she walks alone deep into the woods and then enters an unfamiliar cottage is more than questionable.

But expecting PTOA Readers and Students to forego the laws of the Universe and believe Goldilocks picked the right bowl of porridge is beyond the pale... and most definitely a fairy tale!

 

ONCE UPON A TIME ...

For PTOA Readers and Students who are unfamiliar with the tale, here's the gist:

A family of three bears leaves a cottage and goes on a walk while their lunch of porridge cools down.  The three bowls of porridge are left on the table.

Papa Bear's bowl is the big bowl.

Mama Bear's bowl is the mid sized bowl.

And Baby Bear's bowl is the small bowl.

While the bears are on their walk, a brazen little hussy named Goldilocks enters the cottage and decides she is hungry and wants to eat some porridge.

Goldilocks samples the porridge in the big bowl that belongs to Papa Bear and promptly learns that the porridge is "Too Hot."

PTOA Readers and Students can conclude from her reaction to the taste-test that the spoons are made of metal or some other material with a high "k" factor.  The porridge apparently has a high specific heat capacity, too.

Then Goldilocks samples the porridge in the mid-sized bowl that belongs to Mama Bear and is sad to learn that the porridge is "Too Cold."

Lastly Goldilocks samples the porridge in the small bowl that belongs to Baby Bear and proclaims the porridge is "Just Right" ... and/or "yummmy (yes, with 3 ms)" and "delicious" as shown in the top photo.

Then she gobbles up all of Baby Bear's porridge.

Not in this Universe did that happen.

Armed with their new knowledge of how conduction and convection heat transfer actually work,  PTOA Readers and Students should give some thought as to which of the three bowls would more probably be at the  "Just Right" temperature.

 

SO ... MAKE IT SO

Even better, PTOA Readers and Students should come up with bowl designs and/or any possible enhancements that would make the Goldilocks story become accurate.

By now PTOA Readers and Students can rattle off all the tools in the tool box that can be used to modify the story and make the fairy tale come true.

 

 

For Conductive Heat Transfer the tools are:

• the conductivity coefficient for the material that the bowls are made out of.
• the surface area of the bowls.
• the thickness of the bowls.
• any possible enhancements to Delta T.

 

For Convective Heat Transfer Tools are:

• the amount of porridge in each bowl.
• the heat capacity of the porridge in each bowl.
• any possible enhancements to Delta T.

And don't forget about "rate." The Universe does allow time distortions! Or perhaps changing up the environment with air conditioning/space heaters or perhaps a desk top fan targeted on a certain bowl.

Any combination of conduction and convection heat transfer phenomena that is in sync with the Universe and also jives with the story of Goldilocks and the Three Bears should be considered.

 

Feel like sharing your thoughts on new, improved porridge bowl design?

Consider registering as a PTOA Student.

Registration is free and allows access to PTOA Student Forums ... the venue for discussions with fellow PTOA Students.

LEARN ABOUT FREE PTOA STUDENT REGISTRATION HERE

If you have any difficulty with registration, write Your Mentor an email using the Contact Tab on the PTOA Home Page Menu Bar.

 

HEY, WHAT ABOUT FRED?

The PTOA Heat Transfer Focus Study Area challenged PTOA Readers and Students to assess how heat transfer impacted the plight of Fred the Stick Man back in PTOA Segment 59.

In the event you have not taken the opportunity to ponder Fred's plight return to PTOA Segment 59 at this time and challenge yourself before looking at the below answers.

You do not know what you do not know (nobody does) ...

and you cannot ascertain if you really understand and can therefore apply the principles of heat transfer accurately unless you invest the time in PTOA Do-It-Yourself challenges.

After all ...nobody's watching!

Thank you Fred for helping PTOA Readers and Students get down the difference between temperature and heat!

Answers to Situation One:

Fred likes to drink cold beer with his friends at his favorite tavern, the Leopard Markovinikov.

For the comfort of the patrons, the tavern's temperature is kept at a steady 70 °F throughout the year.

Fred also likes to talk a lot.

Fred orders a frosty mug of beer and starts chatting with his buddies.

By the time Fred stops babbling and takes a sip of his beer, he discovers that his frosty mug is no longer frosty but has warmed up.

Question 1: Why did Fred's cold beer warm up?

The Universe did not like the Delta T between the 70 °F ambient temperature of the Leopard Markovnikov and the frosty cold beer.  Heat was transferred into the beer via convection and conduction.

Question 2: What temperature did Fred's cold beer warm up to?

Fred talked so long with his friends that sufficient time elapsed to equalize the temperature between the ambient temperature of the bar and the beer. Both the bar and the beer end up at  70 °F.

Answers to Situation Two:

Fred drinks too much beer and engages in poor decision making.

Fred decides to go sailing even though he is drunk. He falls into the 50 °F saltwater.

Question 3: Does Fred die of hypothermia because:

• the cold water surrounding Fred's body reduces his temperature below that needed to sustain life?

or

• The Delta T established between Fred's 98.6 °F body temperature and the 50 °F sea temperature causes Fred's body heat to transfer into the cold water in an effort to equalize the two temperatures? THIS IS THE CORRECT ANSWER.

Question 4: In the event you answered that Fred dies because the heat transfers from his body to equalize with the temperature of the sea water...why doesn't the temperature of the ocean increase?

The ocean is too vast of a heat sink for the heat from Fred's body to cause a detectable change in temperature.

Noticeable increases in temperature occur when the heat is being transferred into a more similarly sized area or if the heat transfer is from a smaller yet significantly hotter source.

Answers to Situation 3:

A week later, Fred's body is pulled up as by-catch by the crew of the Fishy-Wish in a purse seine.

Question 5: What temperature is Fred's body?

In a week's time Fred's body has had more than enough time to equalize with the temperature of the ocean at 50 °F.

 

 

TAKE HOME MESSAGES: This PTOA Segment concludes the PTOA Heat Transfer Focus Study Area. 

The PTOA Heat Transfer Focus Study Area Deja Vu Review will follow.

The Deja Vu Review will be followed by the PTOA Heat Transfer Focus Study Area Process Industry Jargon Recap. 

PTOA Readers and Students that read the PTOA Heat Transfer Focus Study Area Segments in the intended sequential order are sufficiently expert in their understanding of Radiant, Conduction, and Convection heat transfer to be able to develop improved designs for heat transfer.

PTOA Readers and Students that read the PTOA Heat Transfer Focus Study Areas Segments in the intended sequential order expertly understand how process industry temperature-changing equipment has harnessed the principles of heat transfer to control the Process Variable Temperature.

©2015 PTOA Segment 00079
PTOA Heat Transfer Focus Study Area

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