Modern Engineering Thermodynamics

Problems 97
Table 3.23 Problem 65
Material p (psia) T (°F) v (ft 3 /lbm) x (if applicable)
Water ? 300. 4.00 ?
Water 300. ? ? 0.500
Water 1.00 1000. ? ?
Mercury 1.00 ? ? 1.00
Ideal gas* 100. ? 5.00 ?
* Use the ideal gas equation of state with R = 50 ft · lbf/(lbm · R.).
Table 3.24 Problem 66
Material p (psia) T (°F) v (ft 3 /lbm) h (Btu/lbm) x (if applicable)
Water 40.0 ? ? ? 0.00
Water ? ? 51.03 1240.5 ?
Water ? 50.0 ? ? 1.00
Ref.-134a 243.86 ? ? ? 0.500
Ref.-134a ? 160. ? ? 1.00
Mercury 100. ? ? ? 1.00
Table 3.25 Problem 67
Material T (°F) p (psia) h (Btu/lbm) x (if applicable)
Ammonia 60.0 60.0 ? ?
Ammonia 60.0 ? ? 0.100
Mercury ? 60.0 38.44 ?
Ref.-134a 60.0 ? ? 1.00
Water ? 1.00 1336.1 ?
Water ? 1.00 ? 0.00
Table 3.26 Problem 68
Material p (psia) T (°F) v (ft 3 /lbm) x (if applicable)
H 2 O 466.3 460. ? 0.00
H 2 O 160. 363.6 ? 1.00
H 2 O 40.0 ? 6.00 ?
H 2 O 1000. 1000. ? ?
Ammonia ? 105 1.00 ?
Ammonia 100. 100. ? ?
Ref.-134a ? 200. ? 0.500
Ref.-134a 325 ? ? 0.00
Mercury 1000. ? ? 1.00
Computer Problems
These problems are designed to be done on a personal computer
using a spreadsheet or equation solver. The problems cannot be
done easily without the use of a computer. They are meant to furnish
an additional learning experience by providing new insights
into the operation of complex thermodynamic systems and
demonstrating the power of the personal computer in generating
and manipulating thermodynamic properties. In these problems,
log is the base 10 logarithm and ln is the base e (i.e., natural)
logarithm.
69. In 1849, William Rankine proposed the following pressuretemperature
relation for saturated water:
logp sat = 6:1007 − 2731:62/T sat − 396,945/Tsat
2
where p sat is in psia and T sat is in R. Develop a computer program
that returns values for p sat in psia when T sat is input in °F. Be sure
to include proper units on all input and output values. Using the
steam tables in Table C.1a of Thermodynamic Tables to accompany
Modern Engineering Thermodynamics, plot the percent error in your
calculated saturation pressure vs. input temperature utilizing data
at 32.0, 100., 200., 300., 400., 500., 600., and 700.°F.