This presentation discusses heat transfer through conduction, convection and radiation. Heat transfer is the exchange of thermal energy between physical systems driven by temperature differences, and always occurs from higher to lower temperature regions. Conduction involves direct contact transfer without molecule movement. Convection refers to transfer through fluid movement, and can be natural or forced. Radiation involves electromagnetic wave transfer without a medium. Examples of each type are provided. Heat transfer finds applications in areas like power plants, engines, buildings and cooling.

1. Presentation
on
HEAT TRANSFER
submitted by: Aaditya soni
b.tech(mechanical)

2. It is the form of energy that could be transfer
from one system to another.
Heat is never contained in a body.
Associated with the motion of molecules.

3. .
Heat transfer is the exchange of thermal
energy between physical systems.
Temperature difference is its driving force.
Always occur from higher temperature region
to lower temperature region.

4. CONDUCTION
CONVECTION
RADIATION

5. Transfer of heat through direct contact.
Without any appreciable motion of
molecules.
Heat flows as a result of temperature
gradient.
From high temperature region to low
temperature region.

6. Through lattice vibration.
By the transport of free electron.

7. STEADY STATE CONDUCTION
TRANSIENT CONDUCTION
RELATIVISTIC CONDUCTION
QUANTUM CONDUCTION

8.  Some materials conduct heat better than others.
Materials that transfer heat well are called
conductors.
Metals are usually good conductors.
Wood, paper and plastic are not.
Materials that stop the transfer of heat are called
insulators (styrofoam, wool, fiberglass).

9. Conduction
The molecules do
not have to be the
same substance.

10. 1. When you heat a metal pan at the bottom, the
heat travels to the other end.
As you heat the metal, the particles vibrate, these
vibrations make the adjacent particles vibrate, and so on
and so on, the vibrations are passed along the metal and
so is the heat, since it’s a metal heat will also by the
transport of electron within the boundary of metal pan.

11. Example 2
The metal conducts heat from the cup
of warm water to the cup of cool water.

12. Your Coke becomes cold because the heat from the soda
transfers into the ice, not the other way around.
Example 3

13. Convection
• Heat transfer by convection is the transfer of
heat through the fluid (liquids and gases)
movement of currents.

14. Types of CONVECTION
NATURAL CONVECTION
FORCED CONVECTION

15. Natural Convection
• Warm fluids rise, cool down, sink, and then
are warmed again.

16. Forced convection
When the convection is accomplish with the
help of forced air or fan then it is known as
forced convection

17. The radiator warms the room by warming the
air around it. Then the warm air transfers heat
to the rest of the room through convection.

18. As air above the road warms up, it rises and is replaced by
cooler air, forming a convection current.

19. Radiation
Heat transfer by radiation is the transfer of heat through
electromagnetic waves.
In the bandwidth of between 0.1 to 100 micro meter.

20. Radiation
• There is no direct contact between the
substances.

21. No need of material or medium
to propagate.
Example

22. This picture illustrates all three type of heat transfer.
Can you identify them all?
Conduction
Radiation
Convection

23. In nuclear power stations
Fast dissipation of heat in engines(Fins)
Heat transfer through composite walls
Architecture.
Heat exchangers.
Cooling techniques.

24. References
JP HOLLMAN (HEAT TRANSFER)
TECHMAX
IIN

25. Thank you
folks!

26. ANY QUESTIONS?