Thermodynamics - 5-2 Energy of a flowing fluid example 1
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- Опубликовано: 22 авг 2024
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ive watched about 6 videos in a row and you explain everything very well, so thank you so much!
dude you are helping me at the moment , literally
thank you very much
Why didn't you use .6L/40min as volume flow rate in order to solve the rest of part a?
May I ask why you are avoiding using density, is it because it is a liquid-gas mixture?
the m dot is different when you plug it into the equation to find the exit velocity. Above you had 2.37x10^-4 kg/s then you plug it in as 0.237x10^-4
Yes, I think I wrote it correctly the first time, it should be 2.37 x 10^-4. I think the answers are correct though.
The exit velocity calculation is approximately correct for the inlet side of the opening, but the pressure will presumably drop to atmospheric pressure 101kpa across the opening. Expansion effects would need to be taken into account for that. Since the steam is at saturation, isentropic expansion should also cause the quality to drop resulting in the exiting steam to be a mixture of liquid and gas.
why did we use vf for finding the mass of those 0.6L instead of vg??
was wondering that to
0.6L of liquid water is evaporated in certain time, so dividing it by vf to obtain the mass rate
Exactly it's steam but we used specific volume of saturated liquid instead of saturated vapor .Still,do not underdtand
yiğit merhaba bu soruyu anladıysan anatabilir misin? Neden vaporın yerinde liquidi kullandık anlamıyorum bir türlü.
@@yigitcan824
why did we find the h using vapor and not liquid?
I think it's because the question asked for the energies of the steam per unit mass. I think you should get the same answer if you used the h for liquid but you would also need to match that with the velocity of the liquid which we don't have. We only have the velocity of the steam. I may be wrong about getting the same answer the other way because I don't really understand if there is a velocity associated with the liquid.
Can we just not do (m dot/rho*cross sectional area) to find the velocity? Thank you. Your videos are magic.
Yes, that would be correct! Just double check that the units work out.
@@engineeringdeciphered Do we use 1000kg/m3 for rho??
does the question ask about the mass flow rate of the stem?
why we calculate the mass flow rate of liquid?
isn't they are diffrent
Thank you !
I see your comment in every video.
how do we know it’s saturated ?
at 10:18 why did we look for at 150 MPa ? shouldnt we look for 150 kPa?? and you said that it is table A5 saturated so there is kPa
When is flow work the (change in pressure)(V) and when is it (Pressure)(V)
U check if the pressure's constant or not
Where do the value of the internal energy come from?
why do we leave them as specific values, why dont multiply by mass? Is it a preference or these questions are mostly solved by finding specific values
I think because for most flowing fluids we don’t usually know the mass. For closed tanks, etc. we’ll sometimes multiply by mass to get the total values. Using specific values allows us to use for systems whether they are big or small. We can compare specific properties.
@@engineeringdeciphered thank you professor, u r the best!
At 6:02 why did you chose to use VA/v
Instead of
rho VA
?
Since the rho for water is basically 1000?
I've tried it and I've got a different (probably wrong) answer but idk why?
I think because this isn’t liquid water so the rho isn’t 1000.
@@engineeringdeciphered thank you a lot
I hope they make you dean of university.
how do we know it’s saturated ?
@@engineeringdeciphered how do we know that the water is saturated?
@@premgandhi4484any time we have a liquid-vapor mixture, the liquid is always saturated liquid, and the vapor is saturated vapor. After all the liquid has turned to vapor, then the vapor will start to become superheated. Or vice versa.