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Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 2 Slide 1 Equilibrium States and.

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Presentation on theme: "Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 2 Slide 1 Equilibrium States and."— Presentation transcript:

1 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 2 Slide 1 Equilibrium States and Processes Processes and cycles

2 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 2 Slide 2 Equilibrium States and Processes Thermodynamic process State 1 State 2 p V T

3 FIGURE 1–28 The P-V diagram of a compression process. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1-7

4 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 2 Slide 4 Equilibrium States and Processes Processes & Equilibrium States What is the state of the system along the process path? What is the state of the system along the process path? p V T S1S1 S2S2 Process Path Quasi-equilibrium process: infinitesimally close to equilibrium state at all times – idealized – best production of work – a standard

5 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 2 Slide 5 Equilibrium States and Processes Thermodynamic process T State 1 State 2 Process 1 p V Process 2 Following a different path is a different process even if the end states are the same. Dashed line between states – non-quasi-equilibrium

6 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 2 Slide 6 Equilibrium States and Processes Thermodynamic cycles P1P1 P2P2 State 1 State 2 Process Path I Process Path II

7 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 2 Slide 7 Equilibrium States and Processes Steady-flow process Steady means no change with time Uniform means no change with location fluid flows through the control volume steadily V, m, and E of the control volume remain constant with time Examples: turbines, pumps, heat exchangers, condensers, boilers, etc.

8 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 2 Slide 8 Equilibrium States and Processes Steady flow process During a steady flow process, fluid properties within the control volume may change with position, but not with time. “Iso-” processes have something held constant: –Isobaric – constant pressure –Isothermal – constant temperature –Isometric – constant specific volume

9 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 2 Slide 9 Equilibrium States and Processes Example: A steam power cycle. Steam Turbine Mechanical Energy to Generator Heat Exchanger Cooling Water Pump Fuel Air Combustion Products System Boundary for Thermodynamic Analysis System Boundary for Thermodynamic Analysis

10 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 2 Slide 10 Equilibrium States and Processes Key concepts and terms Equilibrium Steady Flow Extensive properties Intensive properties Thermodynamic equilibrium Thermodynamic cycle Process Quasi-equilibrium process

11 FIGURE 1–32 The various forms of microscopic energies that make up sensible energy. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1-8 Sum of all microscopic energies is called the internal energy or U (or u)

12 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 12 Application of the Equilibrium Principle Internal energy Made up of sensible energy – from kinetic energies of the molecules and atoms. Plus the latent energy from the phases and weak bonds between molecules Plus the chemical energy from bonds in molecules Plus nuclear energy from strong bonds within the nucleus.

13 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 13 Application of the Equilibrium Principle Macroscopic forms of energy Kinetic Energy, KE or ke Potential Energy, PE or pe Also, magnetism, electricity, surface tension, etc.

14 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 14 Application of the Equilibrium Principle Total Energy, E or e Total energy of a system is the sum of the microscopic energies (internal energy or U) and the external energies (KE and PE) Can also have e = ke + pe + u Thermodynamics only deals with the changes in energy, not absolute energies.

15 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 15 Application of the Equilibrium Principle Energy interactions E is contained or stored in a system Can be changed by energy interactions For a closed system: –If driving force is ΔT, then it is heat transfer –Otherwise the energy interaction is work. For open system, energy of system can also change by energies of input and output streams.

16 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 16 Application of the Equilibrium Principle Energy value Thermal energy (sensible and latent) is unorganized and of low value. Macroscopic kinetic energy is organized and of much more value.

17 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 17 Application of the Equilibrium Principle Temperature & heat...

18 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 18 Application of the Equilibrium Principle Heat & temperature Large body at constant temperature T 1 Large body at constant temperature T 1 Large body at constant temperature T 2

19 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 19 Application of the Equilibrium Principle Zeroth Law of Thermodynamics...

20 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 20 Application of the Equilibrium Principle Two systems in thermal equilibrium with a third system are in thermal equilibrium with each other. The Zeroth Law

21 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 21 Application of the Equilibrium Principle The Zeroth Law Two bodies are in thermal equilibrium if both have the same temperature. Thermal equilibrium is reached between two systems when no heat is transferred when they are put in contact.

22 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 22 Application of the Equilibrium Principle Thermal equilibrium T1T1T1T1 T2T2T2T2 T 1,final T 2,final Initial State: Final State:

23 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 23 Application of the Equilibrium Principle Temperature measurement...

24 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 24 Application of the Equilibrium Principle The mercury in glass thermometer Thermometric property: expansion of Hg with temperature.Thermometric property: expansion of Hg with temperature.

25 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 25 Application of the Equilibrium Principle Thermometric property: Pressure at constant volume.Thermometric property: Pressure at constant volume. Constant volume gas thermometer

26 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. FIGURE 1–45 P versus T plots of the experimental data obtained from a constant-volume gas thermometer using four different gases at different (but low) pressures. 1-12

27 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 27 Application of the Equilibrium Principle Thermometric property: voltage (emf) generated.Thermometric property: voltage (emf) generated. The thermocouple

28 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 28 Application of the Equilibrium Principle Temperature scales Kelvin Scale Triple point of water at P = 1 atmTriple point of water at P = 1 atm T = K Steam point of water at P = 1 atmSteam point of water at P = 1 atm T = K Kelvin Scale Triple point of water at P = 1 atmTriple point of water at P = 1 atm T = K Steam point of water at P = 1 atmSteam point of water at P = 1 atm T = K Celsius Scale Triple point of water at P = 1 atmTriple point of water at P = 1 atm T = 0 o C Steam point of water at P = 1 atmSteam point of water at P = 1 atm T = 100 o C 1 o C = 1 K 1 o C = 1 K Celsius Scale Triple point of water at P = 1 atmTriple point of water at P = 1 atm T = 0 o C Steam point of water at P = 1 atmSteam point of water at P = 1 atm T = 100 o C 1 o C = 1 K 1 o C = 1 K

29 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. FIGURE 1–47 Comparison of temperature scales. 1-13

30 Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 1 Module 3 Slide 30 Application of the Equilibrium Principle Key terms and concepts Adiabatic boundary Adiabatic process Fixed points Heat Isolating boundary Thermometric property Temperature scale Thermometric property Thermometer Zeroth Law of Thermodynamics


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