Heat transfer is the transmission of thermal energy from one region to another as a result of a temperature difference.
Modes of Heat Transfer
Three modes of heat transfer:
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Conduction
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Conduction is the transfer of heat by means of molecular agitation within a material without any motion of the material as a whole. Conduction is the main mode of heat transfer in solids. If the temperature of a solid varies from one point to another, heat transfers from points with higher temperatures to points with lower temperatures in an attempt to establish thermal equilibrium.
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Convection
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Convection is the transfer of heat by means of moving fluids. Convection is the main mode of heat transfer between surfaces of solids and adjacent fluids. The fluid particles act as carriers of thermal energy.
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Radiation
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Radiation is the transfer of heat by means of electromagnetic waves. Unlike conduction and convection, radiation does not require a medium because electromagnetic waves can travel in a vacuum. Radiation effects are more significant at higher temperatures.
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Types of Heat Transfer
Two types of heat transfer analysis:
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Steady state thermal analysis
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Focuses on the thermal conditions of the body when it reaches thermal equilibrium. The time it takes to reach thermal equilibrium is not of interest.
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Transient thermal analysis
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Focuses on the thermal status of the body at different instances of time.
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Thermal stress analysis
Temperature changes can induce significant stresses in the body. Thermal stress analysis calculates stresses, strains, and displacements due to thermal effects.