1 / 34

Thermodynamics II

Learn the basics of thermodynamics, including energy, system properties, equilibrium states, processes, and the first law. Explore properties of pure substances, energy transfer mechanisms, and phase change processes.

michaud
Download Presentation

Thermodynamics II

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Thermodynamics II Lecture 1 Review

  2. Outline • Instructors; Dr. Saleh Abo-Elfadl • Dr. Othman Hassan (othman.hassan@eng.au.edu.eg) • Mid-terms; Midterm1 ….. End of October (tentative) 25/50 • Midterm2 ….. End of November (tentative)25/50 • Bonus… 5/50 attendance of tutorials • Final ……. 100

  3. Definition of Thermodynamics Thermodynamics is the science of : Energy and Power

  4. Dimensions and Units • Any Physical Quantity can be characterized by a Dimension • The magnitudes assigned to the dimensions are called units

  5. Dimensions and Units • Primary or Fundamental Dimensions (Mass, Length, Time, Temperature) • Derived or Secondary Dimensions (Velocity, Energy, Volume…)

  6. Closed and Open Systems • Difference between closed system (control mass) and open system (control volume) • Closed System Open System

  7. Properties of a System • Any Characteristic of a system is called a property (Pressure, Temperature, Volume, Mass) • Intensive properties are independent on the mass or size of the system (Pressure, temperature, …) • Extensive properties (Specific Properties) are dependent on the mass or size of the system (Mass, Volume, …)

  8. State and Equilibrium • State, a condition at which all properties of a system can be measured • At Equilibrium states there is no unbalanced potentials • Thermal Equilibrium (Temperature) • Mechanical Equilibrium (Pressure) • Phase Equilibrium (Phase) • Chemical Equilibrium (Chemical) • To Fully define the state of a system at least two independent properties must be defined

  9. Process and Cycle • Any change in the system state from an equilibrium state to another is a process • The series of states through which the system passes during a process is named a path

  10. Process and Cycle • Isothermal process (Constant temperature) • Isobaric (Constant Pressure) • Isochoric (Constant Volume) • The system is said to undergone a cycle when it returns to its initial state at the end of the process

  11. The Zeroth law of Thermodynamics If two bodies are in thermal equilibrium with a third body, they are also in thermal equilibrium with each other. In other words (if body A is in thermal equilibrium with body B and Body B is in thermal equilibrium with Body C then; Body A is in thermal equilibrium with Body C) This law serves as a basis for the validity of temperature measurements

  12. SI Temperature Scale • Relation between Celsius and Kelvin (absolute) temperatures • T (Kelvin) = T (Celsius + 273.15)

  13. Pressure • Pressure is a normal force exerted by a fluid per unit area • Its units is Pascal (Pa) • 1Pa = 1 N/m2

  14. Absolute and Gauge Pressures

  15. Variation of Pressure with Depth

  16. Forms Of Energy • Kinetic Energy (KE) • Potential Energy (PE) • Internal Energy (U) • Together they form the total Energy (E)

  17. Heat • Heat is the form of energy that is transferred between two systems • Conduction, Convection, and Radiation are the heat transfer mechanisms • Conduction occurs inside solids and fluids • Convection occurs between a solid and a fluid • Radiation occurs between solid bodies regardless if there is a medium between them or not

  18. Work • Work is the energy transfer associated with a force acting through a distance • The rate of work per unit time is named power • There is mechanical, electrical and magnetic works

  19. First Law of Thermodynamics • It is known also as the energy conservation principle • It states that “Energy can be neither created nor destroyed during a process; it can only change forms”

  20. Energy Balance of a System • Total Energy coming in to the system – Total energy leaving the system = Change in total energy of the system

  21. Mechanisms of Energy Transfer • Heat Transfer Q • Work Transfer W • Mass Flow m

  22. Example

  23. Solution

  24. Properties of Pure Substance • Pure substance is a substance that has a fixed chemical composition throughout. • A mixture of two or more phases of a pure substance is still a pure substance as long as the chemical composition of all phases is the same. • Ex. A mixture of ice and liquid water

  25. Phase Change Process of Pure Substance • Compressed Saturated Saturated Liquid-Vapor Mix. Liquid liquid

  26. Phase Change Process of Pure Substance • Saturated Superheated Vapor Vapor

  27. Phase Change Process of Pure Substance

  28. Property Diagrams;1- T-v diagram

  29. 2- P-v Diagram

  30. 3- P-T Diagram

  31. Property Tables

  32. Enthalpy • Enthalpy is the combination of both the internal energy and the flow energy

  33. Saturated Liquid-Vapor Mix. • Quality (x) is defied as;

  34. Properties of Mixture State

More Related