This document defines key concepts in thermodynamics including the three laws of thermodynamics, extensive and intensive properties, thermal equilibrium, and various thermodynamic processes like isochoric, isobaric, and isothermal processes. It also defines other important thermodynamic concepts such as entropy, enthalpy, thermal conductivity, latent and sensible heat, modes of heat transfer, and laws like Fourier's law of conduction and Newton's law of cooling. Gas turbines, steam turbines, and nozzles are also defined.

1. Thermodynamics
1. the branch of physical science that deals with the relations between heat and other
forms of energy (such as mechanical, electrical, or chemical energy), and, by extension,
of the relationships between all forms of energy.
Types of Properties
An extensiveproperty is any property that depends onthe size (or extent) of the
systemunder consideration.
An intensiveproperty is any property that can exist at a point in space.
Thermal equilibrium
In physics and chemistry, a condition in which all parts of a system are at
the same temperature.
Zeroth law of thermodynamics
1. The zeroth law of thermodynamics states that if two thermodynamic systems are
each in thermal equilibrium with a third, then all three are in thermal equilibrium with
each other.
First Law Of Thermodynamics
1. The first law, also known as Law of Conservation of Energy, states that energy cannot
be created or destroyed in a chemical reaction.
Second Law Of Thermodynamics
2. The second law of thermodynamics states that the entropy of any isolated system not
in thermal equilibrium almost always increases.
Third law of thermodynamics:
The entropy of a system approaches a constant value as the temperature approaches absolute
zero. With the exception of glasses the entropy of a system at absolute zero is typically close to
zero, and is equal to the log of the multiplicity of the quantum ground state.
According to Boyle’s Law:
Volume of a given mass of a gas is inversely proportional to pressure if temperature
remains constant
. V  1/P -------------------(1)
According to Charles’s law:
Volume of a given mass of a gas is directly proportional to absolute temperature if pressure

2. remains constant.
V  T ----------------------(2)
isochoricprocess
An isochoric process is a process, in which the volume remains constant.
isobaric process
An isobaric process is a process, in which the pressure remains constant.
isothermal process
An isothermal process is a process, in which the temperature remains constant.
isentropic process
there is no transfer of heat or of matter and the process is putatively reversible.
Joule’s law
states that the internal energy U of a given mass of an ideal gas is independent of
its volume and pressure, depending only on its temperature T.
Gay-Lussac's law
The expression Gay-Lussac's law is used for each of the two relationships named after the French
chemist Joseph Louis Gay-Lussac and which concern the properties of gases, though it is more
usually applied to his law of combining volumes,
reversible process
In thermodynamics, a reversible process -- or reversible cycle if the process is cyclic -- is a process
that can be "reversed" by means of infinitesimal changes in some property of the system
without entropy production.
Irreversible process
In science, a process that is not reversible is called irreversible. a change in the thermodynamic
state of a system and all of its surroundings cannot be precisely restored to its initial state
by infinitesimal changes in some property of the system without expenditure of energy
Adiabatic process
An adiabatic process is one that occurs without transfer of heat or matter between a system
and its surroundings.
Polytrophic process
The term "polytrophic" was originally coined to describe any reversible process on any open
or closed system of gas or vapor which involves both heat and work transfer, such that a
specified combination of properties were maintained constant throughout the process.
Hyperbolic process

3. A process, in which the gas is heated or expanded in such a way that the product of its pressure and
volume (i.e p*v=c ) remains constant, is called a hyperbolic process.
Throttling process
A throttling process is defined as a process in which there is no change in enthalpy from state
one to state two, h1 = h2; no work is done, W = 0;
Modes of heat Transfer
There are three modesof heattransfernamelyconduction,convectionandradiation.
Conduction
Conductionreferstothe heattransferthatoccurs across the medium.Mediumcanbe solidor a fluid.
Convection
Convectionrefersto the heattransferthatwill occur betweenasurface anda movingfluidwhenthey
are at differenttemperatures.
Radiation
In radiation,inthe absence of interveningmedium, there isnetheattransferbetweentwosurfacesat
differenttemperaturesinthe formof electromagneticwaves.
Fourier's law of conduction
Fourier's law, states that the time rate of heat transfer through a material is proportional to the negative
gradient in the temperature and to the area,at right angles to that gradient, through which the heat flows.
Sensible heat
Sensible heat is heat exchanged by a body or thermodynamic system that changes the temperature,and
some macroscopic variables of the body, but leaves unchanged certain other macroscopic variables, such
as volume or pressure.
Latent heat
Latent heat is energy released or absorbed, by a body or a thermodynamic system, during a
constant-temperature process. An example is a state of matter change, meaning a phase
transition, such as ice melting or water boiling.
Newton's Law of Cooling
Newton's Law of Cooling states that the rate of change of the temperature of an object is
proportional to the difference between its own temperature and the ambient temperature (i.e. the
temperature of its surroundings).
Thermalconductivity

4. Thermal conductivity (often denoted k, λ, or κ) is the property of a material to conduct heat.
Entropy
In thermodynamics, entropy (usual symbol S) is a measure of the number of specific
ways in which a thermodynamic system may be arranged, commonly understood as a
measure of disorder.
Enthalpy
A thermodynamic quantity equivalent to the total heat content of a system. It is equal to the
internal energy of the system plus the product of pressure and volume.
Gas turbine
A turbine driven by expanding hot gases produced by burning fuel, as in a jet engine.
Steamturbine
A turbine in which a high-velocity jet of steam rotates a bladed disc or drum.
Nozzle
a cylindrical or round spout at the end of a pipe, hose, or tube used to control a jet of gas or
liquid.