This ppt describes you about some basics of thermal engineering.

1. Fundamentals of
THERMODYNAMICS

2. Introduction
• Thermodynamics is science of energy transfer and its effects on properties.
• Main aim is to convert disorganized form of energy into organized form of
energy in an efficient manner.
• Based on the macroscopic approach which does not require knowledge of
behavior of individual particles and is called classical thermodynamics.

3. System, Surroundings, and Boundary
• A thermodynamic system is defined as quantity of matter or a region in space
chosen for study.
• The region outside the system is called surroundings.
• The real or imaginary surface that separates the system from its
surroundings is called boundary.
• Universe = System + Surroundings

4. Types of System
• Closed System
• Open System
• Isolated System

5. Closed System
• A closed system consists of fixed amount of mass and no mass may
cross the system boundary but energy in form of heat and work may
cross the system boundary.
• The closed system boundary may move.
• Examples of closed systems are sealed tanks and piston cylinder
devices without valves.

6. Open System or Control Volume
• An open system has mass as well as energy crossing the boundary, called a
control surface.
• Examples of open systems are pumps, compressors, turbines, valves and heat
exchangers.

7. Isolated system
• An isolated system is one in which there is no interaction between the
system and surroundings.
• It is of fixed mass and energy, and there is no mass or energy transfer across
the system boundary.
• Examples of isolated system are universe and hot coffee in a well insulated
flask.

8. Closed, Open, and Isolated Systems
Types of Energy Mass Transfer Examples
Closed System Yes No Gas in a sealed
container
Open System Yes Yes Turbines,
pumps, valves
etc.
Isolated System No No Universe,
Thermoflask

9. Properties of a System
• Any measurable characteristic of a system in equilibrium is called a
property.
• The property is independent of the path used to arrive at the system
condition.
• Properties are point functions.
• Properties are exact differentials.
• Properties may be intensive or extensive.

10. Extensive Properties
• Extensive properties depends on size or mass of the system.
• Some extensive properties are:
a. Mass
b. Volume
c. Total Energy
d. Electric Charge
e. Magnetization

11. Intensive Properties
• Intensive properties are independent of size or mass of the system.
• Some intensive properties are:
a. Pressure
b. Temperature
c. Density
d. Velocity
e. Viscosity

12. Important points w.r.t Properties
• Extensive properties per unit mass are intensive properties. For example, the
specific volume v, is defined as
v =
𝑉𝑜𝑙𝑢𝑚𝑒
𝑚𝑎𝑠𝑠
=
𝑉
𝑚
=
𝐸𝑥𝑡𝑒𝑛𝑠𝑖𝑣𝑒
𝐸𝑥𝑡𝑒𝑛𝑠𝑖𝑣𝑒
= Intensive
• Specific Properties are intensive properties.

13. Thermodynamics Equilibrium
A system is said to be in thermodynamic equilibrium if it maintains
a. Thermal Equilibrium ( Equality of Temperature )
b. Mechanical Equilibrium ( Equality of Forces / Pressure )
c. Chemical Equilibrium ( Equality of Chemical Potential )

14. State, Path, and Process
• Condition of a system as defined by properties of system is known as state of
a system.
• Series of state of system through which process occurs is known as path of a
system.
• Any change of state of a system is known as process.
• Some of the processes are-
Process Property held
constant
Isobaric Pressure
Isothermal Temperature
Isochoric Volume
Isentropic Entropy

15. Thermodynamic cycle
• A system is said to have undergone a cycle if the initial and final points are
same.
• Minimum number of processes required for a cycle are 2.
• For a cycle change in property is equal to zero.

16. Pure Substance
• A substance is said to be a pure substance if it is
a. Homogeneous in Chemical Composition.
b. Homogeneous in Chemical Aggregation.
• Examples of pure substance are atmospheric air, steam-water mixture and
combustion products of a fuel.
• Phase ( solid, liquid, gas ) is not considered while determining pure
substance.