Steady Flow Systems - Nozzles and Diffusers | Thermodynamics | (Solved examples)

Learn about steady flow systems, specifically nozzles and diffusers, the equations needed to solve them, energy balance, mass balance and more. A few questions are solved at the end to show how steady flow equations can be utilized.
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What are steady flow systems? (00:00)
Nozzles and Diffusers (03:00)
A diffuser in a jet engine is designed to decrease the kinetic energy (04:20)
Refrigerant-134a at 700 kPa and 120C enters an adiabatic nozzle (06:41)
Steam at 4MPa and 400C enters a nozzle steadily with a velocity (09:20)
Books used:
📘Çengel Yunus A. and M. A. Boles, Thermodynamics: an engineering approach. New York, NY: McGraw-Hill Education, 2016.
📘C. Borgnakke and R. E. Sonntag, Fundamentals of thermodynamics. Hoboken, NJ: Wiley, 2019.

[@navarrelatchman778]

I wish I saw this before my Thermodynamics exam.

[@QuestionSolutions]

I hope you did well on your thermodynamics exam :)

[@nacure360]

this is just fantastic. everything is so simplified. you're helping me so much.

[@QuestionSolutions]

Awesome :) Keep up the great work!

[@Freedomind901]

Literally thank you❤

[@QuestionSolutions]

You're very welcome!

[@mazuja1]

May I know what software you use to make this vid? very nice and easy to understand

[@QuestionSolutions]

I use Illustrator to draw the graphics and After Effects to animate 👍

[@utube9776]

Nice animation buddy you should be professor on reputable engineering college Max work in minimum time just awesome 🙂❤️❤️

[@QuestionSolutions]

Thank you very much! Best wishes with your studies.

[@panagiotisathanasiou7918]

Excellent

[@QuestionSolutions]

Thank you so much!

[@eagle43257]

I think when you increase pressure velocity increases, and the reverse happens when you decrease the pressure. This is because big area means small pressure, and small area means big pressure

[@QuestionSolutions]

👍

[@Jon-xu7jl]

you initially said delta h =Cp(T2-T1) but changed it in the diffuser question to Cp(T1-T2). How do you know which way to put the temperatures? Does it matter?

[@QuestionSolutions]

Please provide timestamps so I know where you're referring to. That way, I can help you out better, thanks!

[@Jon-xu7jl]

@@QuestionSolutions 4:13 for the Cp(T2-T1) and 5:30 for the Cp(T1-T2) . Thanks!

[@QuestionSolutions]

@@Jon-xu7jlAhh, I see, it should be h2-h1 corresponding to T2-T1. They correspond to each other. At 5:30, when we did the energy balance, we got h1-h2, which gives us the corresponding T1-T2.

[@Franky10207]

Sir at the @ 10:59 you have considered mass flow rate and since also there only one inlet and one outlet and can I solve the problem without considering mass flow rate 😊

[@QuestionSolutions]

So the question actually requires you to find the mass flow rate. Since you already found it, might as well use it :)

[@Franky10207]

thank you sir i got it

[@yigitcan824]

Professor I do not understand something, at 3:11 it is said that _diffuser_ increases pressure while reducing velocity_ what's the logic behind that ? I mean how pressure is increasing as velocity decreasing?

[@QuestionSolutions]

I am not sure how to explain the "logic" behind this without going into proofs. But to increase pressure, the velocity needs to drop in a diffuser. For a nozzle, to increase the velocity, the pressure drops. In other words, when we reduce the cone at the right end, the velocity goes us, but the pressure starts to drop. Please see your textbook for proofs :)

[@edwardallotey5742]

Please can I get the name of the steamtables you used for this?

[@QuestionSolutions]

They are at the back of your textbook. The textbook used is in the description if you need it :)

[@huseyingobut7950]

Hi, I love your videos, i was going to ask whether you have a channel for stragth(mechanics) or can you recommend?

[@QuestionSolutions]

I don't have a channel for strength, I also don't know any to recommend. Did you try googling it to see what comes up? There are so many really good, educational channels that teach pretty much anything you want :)

[@huseyingobut7950]

@@QuestionSolutions I know but they don't show as you do. I like this channel because thanks to you I can imagine what is going on in the problem :D Thank you tho

[@QuestionSolutions]

@@huseyingobut7950 I understand. :)

[@ibnrashid6457]

sir, aren't the diffuser v2 supposed to be 0? because the velocity is decreased. I'm confused

[@QuestionSolutions]

Velocity is decreased but it doesn't have to be zero 👍

[@ibnrashid6457]

@@QuestionSolutions so if the question stated that it is 0, then i can use it rght?

[@QuestionSolutions]

If the final velocity is zero, then you would have zero for velocity on the exit side.

[@7mood3bdullah47]

7:43 how is it superheated and 5:34 how is it not superheated because the temperature sat higher than temperature given it means superheated?

[@QuestionSolutions]

Please see this video (kzbin.info/www/bejne/qHzFm4V9ab5gfq8) on how to figure out if a substance is superheated, or a compressed liquid. Especially around 5:50 min mark, I go into how to figure it out.

[@itsyogurt9247]

Why take specific heat of cp? if it is not contant pressure?

[@QuestionSolutions]

I don't know where you're referring to. Please use timestamps.

[@itsyogurt9247]

@@QuestionSolutions my question I believe is general, but for the sake of the video, it's on 5:40. I thought we can only use specific heat cp, if the pressure is constant, but it changes in diffusers and nozzles.

[@QuestionSolutions]

So this is just calculating enthalpy with the assumption that it's an ideal gas. For enthalpy, you use cp, and generally, you will find that the difference in pressure is minimal that it makes little difference. You can see a different problem solved here: pressbooks.bccampus.ca/thermo1/chapter/5-5-application-of-the-mass-and-energy-conservation-equations-in-steady-flow-devices/ check out example number 3 if you need further clarifications. @@itsyogurt9247

[@ashfaqurrahman6968]

why don't you find the value of h1 and h2 from the property table of the 1st math?

[@QuestionSolutions]

You can solve these problems in many different ways. I showcase one method, but as long as you get to the same answer, the path you take doesn't necessarily matter much.

[@Franky10207]

brother pleas make a lot of videos until i become a mechanical engineer

[@QuestionSolutions]

I will do my best :)

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[@QuestionSolutions]

Working on turbines and compressors now. Probably won't get all of them done by next week, but I will do my best. 😔

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[@user-ui6vz3zv8r]

hellpppp pleaseee how to convert m/s to kj/kg in 6:20 im sooooooo confuseddd

[@QuestionSolutions]

This process is called unity conversions. You can see a video of it here: kzbin.info/www/bejne/qZm7n5xrhd2EZtk 1 j/kg = m^2/s^2 If you know that, you can basically convert it whenever you want. Please make sure to understand unity conversions, it'll make your life a lot easier :)