Thermodynamics 49 : Joule Thompson Throttling / Adiabatic Cooling

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In this video I continue with my series of tutorial videos on Thermal Physics and Thermodynamics. It's pitched at undergraduate level and while it is mainly aimed at physics majors, it should be useful to anybody taking a first course in thermodynamics such as engineers etc..
The course covers topics such as the Ideal Gas Law, Entropy, Enthalpy, Gibbs' and Helmholtz' Free Energy, Heat Capacity, Einstein Solids, Taylor and MacLaurin Series / Expansions, phase transformations, thermodynamics identities, the Clausius Clapeyron Relation, Joule Thompson Throttling, Adiabatic Cooling, the paramagnet and of course the all important Laws of Thermodynamics
Thank you for watching and I hope that this matches your requirements. Please feel free to provide feedback via comments and share with your friends.
See my website for more: www.universityphysicstutorials.com
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Опубликовано:

1 сен 2013

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Комментарии : 48

@dimaabed9768 6 лет назад

I've been searching the internet for a whole day to understand throttling valves and couldnt until I found this video. Thanks a lot really !

@youspinmerightrounds 6 лет назад

Glad you liked it! Happy studies

@darcyoqueef2176 4 года назад

wow amazing! finally somebody who knows what they're talking about

@yamiashigaru 9 лет назад

Your explanation in terms of the potential energy was very helpful to me. Thanks for the video.

@youspinmerightrounds 9 лет назад

Great stuff, glad I can help

@raunakkbanerjee9016 6 лет назад

Excellent explanation. It indeed is a tricky concept but you made it look simple !

@youspinmerightrounds 6 лет назад

Tricky is the word! I'm glad I could help. Happy studies!

@wdeadh3721 6 лет назад

At That Day..I Decided To Learn How Refrigerators Works...So, I Searched And Watched Some Videos, But I Understood Mostly How After Watching This Vid...Thanks!

@abhijith3627 4 года назад

i was really looking for a good explanation thank you sir

@colinread2833 4 года назад

Thanks for the clear and helpful explanation.

@davidg2717 9 лет назад

Hey Adam, I think you described the effect very well. I just have one question. At the end, you said that when people were trying to cool hydrogen, they used the Joule Thompson effect. On wikipedia, the information of the Joule Thompson effect says that all gasses follow this model except for the exception of Hydrogen, Helium, and Neon. If I recall correctly, hydrogen has a negitive JT coeffecient, meaning it would heat up when the pressure decreases, right?

@abdhoom786 8 лет назад

Seriously you explained it well. Thanks

@small_ed 2 года назад

Interesting presentation. One small comment...to my understanding, pressure cannot be removed from the work integral unless constant (I've never seen PfVf - PiVi as a solution).

@talhaiqbal 6 лет назад

Sir thank you for such an amazing explanation.

@houdalmayahi3538 5 лет назад

Nice explanation!

@louisverbeke9578 6 лет назад

Why didn’t you mention anything about the inversion temperature and the fact that the temperature could aso rise while expanding?

@mahroos6 6 лет назад

Thanks, great work!

@somkanskar8931 6 лет назад

Why is potential energy increasing when the distance between molecules is increased because repulsive force is going to be decreased hence the potential energy should decrease?

@p4alls 9 лет назад

Great video ,helped a lot,thanks :)

@younessdiouane3829 6 лет назад

Thank you a lot

@youspinmerightrounds 6 лет назад

You're very welcome. Happy studies!

@riturajphukan632 6 лет назад

This was brilliant :)

@ankitk2610 6 лет назад

JT Throttle can cause increase in temperature also if the initial pressure at a particular temperature is more than inversion point pressure,So how will you physically define heating?

@pokk700 8 лет назад

So, why is the mesh/porous valve necessary? Is this to avoid giving the gas molecules additional kinetic energy?

@Sonserf369 8 лет назад

It is in order to create the high and low pressure regions. If you didn't have an obstruction, then the gas would expand equally across the whole tube and the pressure would be the same everywhere. By creating an obstruction, you "clog" the tube, and so fewer molecules will make it through to the otherside; less molecules means more space, which means lower pressure.

@hibamolitas1786 8 лет назад

thank u

@waldo2413 5 лет назад

I have some questions how hard is it to make liquid nitrogen doing the method

@edge21str 9 лет назад

Question: When you blow air out of your mouth (like trying to blow out a candle) is air cooled by the same process?

@KevinWillis2 9 лет назад

edge21str A fan, like the mouth, is not cooling the air. It feels cooler because of the effect of conduction and slightly because of evaporation on the skin. The nerves in the body detect that heat is leaving the body via the air and you sense that the area is cold. The air being blown out of the mouth is the same temperature as it was before it left your mouth. The effect in this video would be negligible in your proposed scenario.

@hikahoper9853 7 лет назад

what happen with He gas? it cannot affect this effect, isnt it? and i dont know why yet

@tuck295q 10 лет назад

Wait wait, at 9:41, why is potential energy increases to be more than positive 1 when you designate the potential energy of attraction to be negative. If you keep increasing the distance of particles apart, attractive force should dominate and become negative sign. Particles that get too close together will have their repulsive force dominate which have their potential energy becomes positive. Did you got swapped somehow?

@TheUMESH34 10 лет назад

im thinking like this, let the potential energy at initial postion of the molecules be "P". If we decrease or increase the distance between the molecules we produce potential energy i.e. making it more then P,which is trying to bring it back to its original state

@ZoyaKhan-we8zi 7 лет назад

why helium show heating effect at room temperature ??

@carlangelodelacruz7524 6 лет назад

Zoya Khan All other gases are below their inversion temperature at room temp. Only hydrogen and helium gas are above their inversion temperatures at room temp which results to a warming effect upon expansion..

@abcdef2069 8 лет назад

can you explain how you get Uf - Ui = Pi Vi - Pf Vf in your 1st statement?

@4Caste 8 лет назад

U = q (heat) + w (work), but in an adiabatic process there is no heat transfer so q=0. so you are just left with U=w. The work for this process is going to be PV.

@mohsenkhaleel924 8 лет назад

also where does the energy go ??

@mohsenkhaleel924 8 лет назад

?? i couldn't understand why the pothential energy of two molecules apart will be larger than when they are closer??

@alexasfo7690 8 лет назад

you've misspelled "Thomson". Good work though

@Jamesparkr 4 года назад

I would much prefer if you just use the diagram, the formulas where confusing and it seemed like you where showing off using them, or maybe use the diagram first then use your formulas.

@Luzt. 6 лет назад

Sir, you do not present any coherent, step by step reasoning. You say sentences which make sens as separate units of information, but they do not follow any path. You do not understand what really happens. E.g. the pistons - what do they do, what are they for, can we do without them, what happens in real situation (e.g. in refrigeration)?

@youspinmerightrounds 6 лет назад

Hi there, thanks for your feedback - it's always great to get. I think you're right. It's a long time since I recorded this video and it's far from perfect. I'd probably do a better job of it these days, but 'unfortunately' in that sense, my old videos are here to stay. I don't have time to re-record those. That said, here are some recent videos which may support what I'm saying: ru-vid.com/group/PLclocfvsabE1tmz0qxuMPoIL3pLNbTnAv. Best of luck and happy studies.

@artsyfartsy7362 8 лет назад

Still very helpful, but you stammered and corrected yourself too much! :)

@megag52 10 лет назад

maybe this video is designed for a neich audience, but as a layman who just wanted to know a bit more about Joule Thompson Throttling and what is actually going on with the molecules, this was terrible. the maker could learn a lot from the khan academy

@youspinmerightrounds 10 лет назад

Thank you for your feedback.

@KevinWillis2 9 лет назад

Sam Dawkins If you expected a layman explanation, why did you continue to watch a video that mentions "University Physics" at the very beginning? Then you have the audacity to claim the video was "terrible". Yikes!

@megag52 9 лет назад

Kevin Willis you actually said "yikes". are you a cartoon character?