Using the appropriate table, determine the change in specific entropy in kJ/kg-K for:
a.) Water: P1 = 10 MPa, T1 = 400oC and P2 = 10 MPa, T2 = 100oC.
b.) R-134a: H1 = 211.44 kJ/kg, T1 = - 40oC and P2 = 5 bar, x2 = 1.0.
c.) Air (IG): T1 = 7oC, P1 = 2 bar and T2 = 327oC, P2 = 1 bar.
d.) Hydrogen (H2, IG): T1 = 727oC, P1 = 1 bar and T2 = 25oC, P2 = 3 bar.
4 comments:
How are we supposed to use the IG property tables? I understand the steam tables well enough...
anon:
I think you may be missing class. The ideal gas properties are functions of T only. Given T, interpolate to get any other property. Given any of the properties int he table you can interpolate to get T. This is very similar to the other tables, only simpler. Just keep in mind that S is a fxn of P even for ideal gases ! S not= Snought. Use the 1st or 2nd Gibbs Eqns with Snought to find deltaS.
Hi Professor,
For this problem, which H1 is most updated 111.44 KJ/kg like on this blog or 211.44 KJ/kg like on the excel version?
Anon:
Doh, that was a typo in this blog. I just fixed it. H1 = 211.44 kJ/kg.
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