H2O, Ammonia, R12, R22, R134a, Nitrogen, Methane

1
Determining Properties For Fundamentals of
Thermodynamics, Sonntag, Borgnakke, and Van
Wylen NOTE In General y v, u, h, and/or s
No/ Dont Know
Start
Not Ideal Gas Z Pv/RT Use compressibility
charts for u and h
Ideal Gas?
No Then Gas
Calc. Z Z ? 1?
No

H2O, Ammonia, R-12, R-22, R-134a, Nitrogen,
Methane?
Yes
Yes
Yes
Pv RT u and h fn of T (not P)
Sat. Liq.-Vap. Mixture y yf x(yg yf)
Sat. Tables _at_ T is P PSAT or _at_ P is T
TSAT or _at_ T or P is yf ? y ? yg
Yes
Air, N2, N, O2, O, CO2, CO, H2O, OH, H2, H, NO,
NO2
Yes Then Saturated T TSAT P PSAT
yf lt y lt yg 0 Or 0 lt x lt 1
Monatomic Gas? E.g., He, Ar, Ne
No
Yes
No
No
Yes
No
y yf x 0
y yf or x 0
Yes Then Sat. Liq.
Assume cp and cv Constant?
Yes
CV 3R/2Constant CP 5R/2Constant
Get Cv and CP from table at TAVG
No
No
Yes Then Sat. Vapor
y yg x 1
Sat. Tables _at_ T is P lt PSAT or _at_ P is T gt
TSAT or _at_ T or P is y gt yg
y yg or x 1
Use Gas Tables for u, h, s0 ?ss20- s10-Rln(p2/p1)
?u CV ?T ?h CP ?T ?s CVln(T2/T1)
Rln(v2/v1) ?s CPln(T2/T1) -Rln(p2/p1)
Superheated Vapor Use Superheated Vapor Tables
Yes
If Air and Isentropic
No Compr. Liq.
If Isentropic
Use Air Tables for pr and vr P2/P1
Pr2/Pr1 v2/v1 vr2/vr1
Use ICL Approx y(T, P) yf(T) h(T, P) uf(T)
Pvf(T)
Compr. Liq. Tables Available?

Yes
Yes
Use Compr. Liq. Tables
Both superheated vapor and ideal gas property
tables available for H2O and Nitrogen