Thermodynamics 49 : Joule Thompson Throttling / Adiabatic Cooling

[@dimaabed9768]

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]

Glad you liked it! Happy studies

[@davidg2717]

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?

[@louisverbeke9578]

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

[@somkanskar8931]

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?

[@yamiashigaru]

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

[@youspinmerightrounds]

Great stuff, glad I can help

[@raunakkbanerjee9016]

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

[@youspinmerightrounds]

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

[@small_ed]

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).

[@wdeadh3721]

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!

[@darcyoqueef2176]

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

[@alexasfo7690]

you've misspelled "Thomson". Good work though

[@waldo2413]

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

[@ankitk2610]

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?

[@ZoyaKhan-we8zi]

why helium show heating effect at room temperature ??

[@carlangelodelacruz7524]

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..

[@Luzt.]

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]

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: kzbin.info/aero/PLclocfvsabE1tmz0qxuMPoIL3pLNbTnAv. Best of luck and happy studies.

[@abhijith3627]

i was really looking for a good explanation thank you sir

[@colinread2833]

Thanks for the clear and helpful explanation.

[@pokk700]

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

[@Sonserf369]

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.

[@tuck295q]

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]

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

[@hikahoper9853]

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

[@abdhoom786]

Seriously you explained it well. Thanks

[@edge21str]

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

[@KevinWillis2]

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.

[@artsyfartsy7362]

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

[@houdalmayahi3538]

Nice explanation!

[@talhaiqbal]

Sir thank you for such an amazing explanation.

[@younessdiouane3829]

Thank you a lot

[@youspinmerightrounds]

You're very welcome. Happy studies!

[@p4alls]

Great video ,helped a lot,thanks :)

[@abcdef2069]

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

[@4Caste]

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]

also where does the energy go ??

[@hibamolitas1786]

thank u

[@mahroos6]

Thanks, great work!

[@riturajphukan632]

This was brilliant :)

[@Jamesparkr]

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.

[@mohsenkhaleel924]

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

[@megag52]

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]

Thank you for your feedback.

[@KevinWillis2]

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]

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

[@-_-who314]

@@megag52 probably is, yikes! ... and so am I...