1. Thermodynamics Lecture Series
Assoc. Prof. Dr. J.J.
Pure substances – Property tables and Property Diagrams
Applied Sciences Education Research Group (ASERG)
Faculty of Applied Sciences
Universiti Teknologi MARA

2. Quotes
“You do not really understand something unless you can explain it to your grandmother.”
(Albert Einstein)

3. State the meaning of pure substances
Introduction
Objectives:
State the meaning of pure substances
Provide examples of pure and non-pure substances.
Read the appropriate property table to determine phase and other properties.
Sketch property diagrams with respect to the saturation lines, representing phase and properties of pure substances.

4. FIGURE 1–5 Some application areas of thermodynamics.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
FIGURE 1–5 Some application areas of thermodynamics.
Application
1-1

5. Example: A steam power cycle.
Turbine
Mechanical Energy
to Generator
Heat
Exchanger
Cooling Water
Pump
Fuel
Air
Combustion
Products
System Boundary
for Thermodynamic
Analysis
Steam Power Plant

6. Steam Power Plant

7. Copyright © The McGraw-Hill Companies, Inc
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
FIGURE 1–17 A control volume may involve fixed, moving, real, and imaginary boundaries.
Open system devices
1-5

8. Open system devices
Throttle
Heat Exchanger

9. Properties of Pure Substances
CHAPTER 2
Properties of Pure Substances
Title:

10. Pure substances Substance with fixed chemical composition
Can be single element: Such as, N2, H2, O2
Compound: Such as Water, H2O, C4H10,
Mixture such as Air,
2-phase system such as H2O.
Responsible for the receiving and removing dynamic energy (working fluid)

11. Water interacts with thermal energy
Phase Change of Water
T, C 30
, m3/kg 1
H2O:
C. liquid
P = 100 kPa
T = 30 C
Qin
H2O
Sat. liquid
Qin
P = 100 kPa
T = 99.6 C
99.6
2 = kPa
Water interacts with thermal energy

12. Water interacts with thermal energy
Phase Change of Water
99.6
2 = kPa
T, C 30
, m3/kg 1
P = 100 kPa
T = 99.6 C
H2O:
Sat. Liq.
Sat. Vapor
Qin
H2O
Sat. liquid
Qin 3
Water interacts with thermal energy

13. Water interacts with thermal energy
Phase Change of Water
P = 100 kPa
T = 99.6 C
99.6
2 = kPa
T, C 30
, m3/kg 1 3
H2O:
Sat. Vapor
Qin
H2O:
Sat. Liq.
Sat. Vapor
Qin
4 = kPa
Water interacts with thermal energy

14. Water interacts with thermal energy
Phase Change of Water
5 = kPa, 150°C
P = 100 kPa
T = 99.6 C
H2O:
Sat. Vapor
Qin
H2O:
Super
Vapor
P = 100 kPa
T = 150 C
Qin
99.6
2 = kPa
T, C 30
, m3/kg 1
4 = kPa 3
3 = [f + x f kPa
1 =
150 5
Water interacts with thermal energy

15. Water interacts with thermal energy
Phase Change of Water
P = 100 kPa
T = 30 C
H2O:
C. liquid
Qin
P = 100 kPa
T = 99.6 C
H2O
Sat. liquid
Qin
H2O:
Sat. Liq.
Sat. Vapor
P = 100 kPa
T = 99.6 C
Qin
P = 100 kPa
T = 99.6 C
H2O:
Sat. Vapor
Qin
P = 100 kPa
T = 150 C
H2O:
Super
Vapor
Qin
Water interacts with thermal energy

16. Phase Change of Water T, C 100 kPa 150 99.6 30 , m3/kg5
T, C 30
, m3/kg 1
5 = kPa, 150°C
3 = [f + x f kPa
1 =
99.6
2 = kPa 3
4 = kPa
Compressed liquid: Good estimation for properties by taking y = where y can be either , u, h or s.

17. Copyright © The McGraw-Hill Companies, Inc
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
FIGURE 2-11 T-v diagram for the heating process of water at constant pressure.
2-1

18. Phase Change of Water T, C 1000 kPa 100 kPa 179.9 10 kPa 99.6 45.8
, m3/kg
10 kPa
179.9
99.6
kPa
kPa
45.8

19. T –v diagram: Multiple P
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
FIGURE 2-16 T-v diagram of constant-pressure phase-change processes of a pure substance at various pressures (numerical values are for water).
T –v diagram: Multiple P
99.6
45.8
179.9
2-2

20. T –v diagram: Multiple P
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
FIGURE 2-18 T-v diagram of a pure substance.
T –v diagram: Multiple P
2-3

21. T – v diagram - Example P, kPa T,  C 50 70 Psat, kPa Tsat, C 81.33
, m3/kg C
T, C
, m3/kg
Phase, Y?
Compressed Liquid,
T < Tsat
50 kPa
81.3
3.240 70
C =

22. T-  diagram with respect to the saturation lines
T – v diagram - Example
P, kPa
, m3/kg
200
1.5493
Phase, Why?
Sup. V.,  >g
Psat, kPa
Tsat, C
120.2
T,  C
400
T, C
, m3/kg
400
kPa =
200 kPa
T-  diagram with respect to the saturation lines
 =
374.1
120.23
kPa =

23. T-  diagram with respect to the saturation lines
T – v diagram - Example
P, kPa
u, kJ/kg
1,000
2,000
Psat, kPa
Tsat, C
179.9
T,  C
179.9
Phase, Why?
Wet Mix., uf < u < ug
T, C
, m3/kg
1,000 kPa
T-  diagram with respect to the saturation lines
374.1
kPa =
179.9
kPa = 
 = [f + x f kPa

24. Property Table Saturated water – Pressure table
P, kPa 10 50
P, MPa
0.100
1.00
22.09
Sat. temp.
Tsat, C
45.81
81.33
99.63
179.91
311.06
374.14
Specific volume, m3/kg
f, m3/kg
g, m3/kg
14.67
3.240
1.6940
Specific internal energy, kJ/kg
uf, kJ/kg
ufg, kJ/kg
ug, kJ/kg
191.82
2246.1
2437.9
340.44
2143.4
2483.9
417.36
2088.7
2506.1
761.68
1822.0
2583.6
1151.4
2544.4
2029.6