Introduction :
The energy in transit is call heat. Heat is a form of energy. The molecules of a substance are in parallel motion. The mean kinetic energy per molecule of the substance is proportional to its absolute temperature.
Heat transfer defined as ” The transmission of energy from one region to another as a result of temperature gradient”. In heat transfer the driving potential is temperature difference whereas in mass transfer the driving potential is concentration difference. In mass transfer we concentrate upon mass motion which result in changes in composition, and are caused by the variations in concentration of the various constituent species.
Use of Heat Transfer:
- To estimate the rate the flow of energy as heat through the boundary of a system under study.
- To determine the temperature field under steady and transient condition.
Applications of heat transfer:
- Design of thermal and nuclear power plants.
- Refrigeration and air-conditioning.
- Internal combustion engines.
- Heat treatment of metals, Design of furnaces.
| BASIC CONCEPT |
Thermodynamics:
Thermodynamics deals with the relations among heat, work and properties of the system which are in equilibrium. It has four laws, zeroth law, first law, second law and third law. The theme of the four laws are
- Zeroth law deals with thermal equilibrium.
- First law defines concept of internal energy.