Introduction To Heat Transfer

Heat transfer, a branch of thermal engineering that concerns the transfer of thermal energy from one physical system to another. Heat transfer is also classified into various mechanisms, such as heat conduction, convection, thermal radiation, and phase-change transfer. Engineers also include the transfer of mass of differing chemical species, either cold or hot, to achieve heat transfer.

Conduction, also known as diffusion, is the direct microscopic exchange of kinetic energy of particles through the boundary between two systems. Let us consider a body at a different temperature from another body or its surroundings, heat flows so that the body and the surroundings reach the same temperature at thermal equilibrium. Such spontaneous transfer of heat always occurs from a region of high temperature to another region of lower temperature, as required by the second law of thermodynamics.

Transfer of the thermal radiation is the transfer of energy by transmission of electromagnetic radiation described by black body theory.

Heat Dissipation by a Heat Sink:

A heat storage device or a heat sink is a component that transfers heat generated within a solid material to a fluid medium, such as air or a liquid. Examples related to heat sinks are the heat exchangers used in refrigeration and air conditioning systems, and the radiator in a car (which is also a heat exchanger). This also helps to cool electronic and optoelectronic devices such as CPU’s, higher-power lasers, and light-emitting diodes (LEDs). It uses its extended surfaces to increase the surface area in contact with the cooling fluid.

Heat Exchangers:

Heat exchanger device is a tool built for efficient heat transfer from one fluid to another, whether the fluids are separated by a solid wall so that they never mix, or the fluids are in direct contact. Heat exchanging device are widely used in refrigeration, air conditioning, space heating, power generation, and chemical processing. Example of a heat exchanger is a car's radiator, in which the hot coolant fluid is cooled by the flow of air over the radiator's surface.