Engineering Thermodynamics (MEL140)

Course co-ordinator:

Subhra Datta

Room no. : III-175Email : subhra@gmail.com, subhra.datta@mech.iitd.ac.inPh : 01126591054

Course outlineTopic Number of Lectures

Introduction and basic concepts 2

Energy, energy transfer and the first law of thermodynamics 2

Properties of pure substances 3

Energy analysis of closed systems 3

Mass and Energy analysis of control volumes 4

The second Law of thermodynamics 6

Entropy and the second law 5

Exergy analysis 4

Thermodynamic property relations 4

Air standard cycles 2

Vapor power cycles 2

Refrigeration cycles 2

Project presentations 3

Total 42

Course outline (contd.)

Evaluation policy: Minor 1: 20 Minor 2: 20 Major: 40

Projects and assignments: 20

Textbook: Cengel, Y.A., and Boles, M.A., Thermodynamics an Engineering Approach, Tata McGraw-Hill., New York, 7th Edition. References: Moran, M.J., and Shapiro, H.N., Fundamentals of Engineering Thermodynamics, John Wiley, New York, Sixth edition. P. K. Nag, Engineering Thermodynamics, Tata Mcgraw-Hill, 2005.

What is thermodynamics?

• Study of energy and relationship between its various forms.

• Historically, thermodynamics emerged through studies of how heat is related to other forms of energy.

History of thermodynamics

• How can we make heat engines (convert heat to work)? Savery (1650-1715), Newcomen (1664-1729), Watt (1736-1819).

• What is heat? Lavoisier (1743-1794).• What is heat? Can mechanical work be converted to heat? Count

von Rumford (1753-1814), Mayer (1814-1878), Joule (1818-1889),• How heat engines work? How efficient can heat engines be made?

Sadi Carnot (1796-1832), Kelvin (1824-1907), Rankine (1820-1872).• What determines the (im)possibility and direction of natural

processes? Kelvin, Clausius, Planck(1858-1947),Gibbs (1839-1903), Caratheodory (1873-1950), Clapeyron (1799-1864).

• How is the average behavior of a collection of particles are related to their individual behaviors during processes? Maxwell (1831-1879), Boltzmann (1844-1906),Planck(1858-1947), Gibbs (1839-1903).

Discuss the history of thermodynamics focusing on the contributions of

• Project 1: Savery, Newcomen, Watt• Project 2: Count von Rumford, Mayer, Joule (Group 2)• Project 3: Carnot, Kelvin, Rankine (Group 3)• Project 4: Clausius, Clapeyron, Caratheodory (Group 4)• Project 5: Gibbs, Planck (Group 5)The “Project Groups” are different (see next slide) from the system-assigned “Tutorial Groups”. See course website for Project 1 groups.

Laws of thermodynamics

• First Law: The total quantity of energy in the universe is fixed.

• Second Law: Energy possesses quality; actual processes occur in the direction of decreasing energy quality.

System and surroundings

• System: a region chosen for thermodynamic analysis

• Surroundings: The part of the universe other than the system

• Boundary: The real or imaginary surface separating the system from its surroundings.

Types of system

• Isolated system: neither energy nor mass crosses its boundary

• Closed system: energy but no mass crosses its boundary

• Open system (control volume): mass and energy both cross its boundary

Example of closed systems

Examples of open systems

heat

Pure substance and phase and simple compressible system

– Pure substance: quantity of matter with uniform chemical composition

– Phase: quantity of matter with uniform physical properties (e.g. density, refractive index) separated by distinct boundaries from other phases. A substance can exist in either solid, liquid and gas phase.

Example of phases and pure substance

2P

1P2P

3P

Not puresubstances

2P

Property

• Any characteristic that can be ascribed to a system e.g. volume (V), temperature (T) and pressure (P).

• Extensive property: depends on the size of the system e.g. volume, mass

• Intensive property: independent of system size: pressure, temperature, density

• Non-property: work, heat