Содержание
- 2. Thermodynamics Thermodynamics is the study of the effects of work, heat, and energy on a system
- 3. Getting Started All of thermodynamics can be expressed in terms of four quantities Temperature (T) Internal
- 4. Classical vs Statistical Classical thermodynamics concerns the relationships between bulk properties of matter. Nothing is examined
- 5. Introduction According to British scientist C. P. Snow, the three laws of thermodynamics can be (humorously)
- 6. 1.0 You can’t win (1st law) The first law of thermodynamics is an extension of the
- 7. Slide courtesy of NASA
- 8. 1.1 Process Terminology Adiabatic – no heat transferred Isothermal – constant temperature Isobaric – constant pressure
- 9. 1.1.1 Adiabatic Process An adiabatic process transfers no heat therefore Q = 0 ΔU = Q
- 10. 1.1.2 Isothermal Process An isothermal process is a constant temperature process. Any heat flow into or
- 11. 1.1.3 Isobaric Process An isobaric process is a constant pressure process. ΔU, W, and Q are
- 12. 1.1.4 Isochoric Process An isochoric process is a constant volume process. When the volume of a
- 13. 1.2 Heat Capacity The amount of heat required to raise a certain mass of a material
- 14. 1.2.1 Heat Capacity of Ideal Gas CV = heat capacity at constant volume CV = 3/2
- 15. 2.0 You can’t break even (2nd Law) Think about what it means to not “break even”.
- 16. Slide courtesy of NASA
- 17. 2.1 Concerning the 2nd Law The second law of thermodynamics introduces the notion of entropy (S),
- 18. 2.2 Implications of the 2nd Law Time marches on If you watch a movie, how do
- 19. 2.3 Direction of a Process The 2nd Law helps determine the preferred direction of a process
- 20. 2.4 Heat Engine A device which transforms heat into work is called a heat engine This
- 21. 2.4.1 Cycles It is beyond the scope of this presentation, but here would be a good
- 22. 2.4.2 The Carnot Cycle Image from Keta - Wikipedia
- 23. 2.4.2.1 Carnot explained Curve A (1 → 2): Isothermal expansion at TH Work done by the
- 24. 2.4.2.2 Area under PV curve The area under the PV curve represents the quantity of work
- 25. 2.5 Engine Efficiency The thermal efficiency of a heat engine is e = 1 + QC/QH
- 26. 2.6 Practical Uses Automobile engines, refrigerators, and air conditioners all work on the principles laid out
- 27. 3.0 You can’t get out (3rd Law) No system can reach absolute zero This is one
- 28. 3.1 Implications of 3rd Law MIT researchers achieved 450 picokelvin in 2003 (less than ½ of
- 29. 4.0 The Zeroth Law The First and Second Laws were well entrenched when an additional Law
- 30. Slide courtesy of NASA
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