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

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

yes, what do you need to know? keith(fridge/aircon engineer, hence the ice),

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

miks are you using the posted chart?

yes thats the one weve been given

keith, would it be easier if we both go on the chat function of the site? might be easier than back and forth posting

yes but not used it before

quote:

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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

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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....

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!

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)

Good old Eastop & Mconkey

thermodynamics

quote:

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Originally posted by big-vee-twin
Good old Eastop & Mconkey

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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!