Miks15
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| posted on 20/1/11 at 11:22 PM |
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anyone know anything about pressure - enthalpy charts?
Right ive got a pressure enthalpy chart, and i need to know the enthalpy of the fluid at given pressure and temperatures.
But im not sure what lines to use, can anyone help? here is the chart:
 
So say for a pressure of 2 bar at 80 degree C, what would the enthalpy be?
Please help
Cheers
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Miks15
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| posted on 20/1/11 at 11:29 PM |
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And also what are the two sections for, is it something to do with saturation, because at 80 degree its a vapour, whereas at 20 its not, and i think i
need to read off to different parts of the graph for that :S
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keithice
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| posted on 21/1/11 at 12:28 AM |
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yes, what do you need to know? keith(fridge/aircon engineer, hence the ice),
Smile and wave boys.... Smile and wave....
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Miks15
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| posted on 21/1/11 at 12:38 AM |
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keith if you can help i would owe you big time.
Basically we have done an experiment at uni (i saw we, the post grad did it, we just took down the results, he then sent us on our merry way) and i
now have to right up the lab report. We have to work out thermal efficiency of the practical rankine cycle on a small scale test. So i need to know
the enthalpys at 4 different points (between the 4 different processes) so i can work out the heat transfers from source and to the sink, and also the
work out at the turbine, and in from the pump.
I have pressures and temperatures.
So for example i have for the first set of results:
Before Vapour generator : abs pressure - 3 Bar, temp 18.5 C
After vapour generator : abs pressure - 3 Bar, temp 83 C
after turbine, before condenser - 1.05 Bar, and i assume still 83C
after condenser, 1.05 Bar, 17.5 C
Can you give me a hand indetifying the enthalpys for these values?
Thanks
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keithice
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| posted on 21/1/11 at 12:59 AM |
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miks are you using the posted chart?
Smile and wave boys.... Smile and wave....
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Miks15
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| posted on 21/1/11 at 01:01 AM |
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yes thats the one weve been given
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Miks15
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| posted on 21/1/11 at 01:02 AM |
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keith, would it be easier if we both go on the chat function of the site? might be easier than back and forth posting
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keithice
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| posted on 21/1/11 at 01:06 AM |
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yes but not used it before
Smile and wave boys.... Smile and wave....
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Alan B
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| posted on 21/1/11 at 01:36 AM |
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quote:
Originally posted by Miks15
keith, would it be easier if we both go on the chat function of the site? might be easier than back and forth posting
What?...and deprive us of this scintillating discussion???
Seriously guys we may learn something...certainly takes me back a few years
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keithice
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| posted on 21/1/11 at 01:46 AM |
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sorry alan... ended up on the phone as it was easier to try and explain it and of course it's a turbine not a compressor (which I would be
using...) but I think mik15 cracked it....
Smile and wave boys.... Smile and wave....
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Miks15
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| posted on 21/1/11 at 02:13 AM |
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i think i have cracked it now, locostbuilders to the rescue 
Just proves you should never leave assignments til the night before... especially when you dont fully understand the assignment
Couple more hours and it should all be done... then i can finally go to bed!
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mcerd1
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| posted on 21/1/11 at 08:13 AM |
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sounds like your doing second year mech eng (or first year south of the border)
I'm glad someone else answed this, I'd have had to get my old thermodynamics books out (and I hated thermodynamics)
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big-vee-twin
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| posted on 21/1/11 at 09:18 AM |
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Good old Eastop & Mconkey
Duratec Engine is fitted, MS2 Extra V3 is assembled and tested, engine running, car now built. IVA passed 26/02/2016
http://www.triangleltd.com
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SeanStone
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| posted on 21/1/11 at 09:18 AM |
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thermodynamics 
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mcerd1
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| posted on 21/1/11 at 09:36 AM |
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quote:
Originally posted by big-vee-twin
Good old Eastop & Mconkey
thats the one
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Miks15
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| posted on 21/1/11 at 10:39 AM |
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yep im second year
Really should have started this assignment sooner! I will learn for next time.
5 in the morning is not a time i want to be finishing a piece of work!
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