Heat Transfer Mechanisms
1. Conduction of Heat Transfer Mechanisms
Definition: Transfer of heat through a material without any movement of the material itself.
Mechanism: Occurs due to the transfer of kinetic energy between molecules or atoms.
Examples: Heat flowing through a metal rod when one end is heated.
Factors: Thermal conductivity of the material, cross-sectional area, temperature gradient, and thickness.
2. Convection
Definition: Transfer of heat by the physical movement of a fluid (liquid or gas).
Mechanism: Warmer fluid becomes less dense and rises, while cooler fluid sinks, creating a convective current.
Examples: Boiling water, where hot water from the bottom rises to the top.
Factors: Fluid properties (density, viscosity), temperature difference, surface area, and gravity.
3. Radiation
Definition: Transfer of heat in the form of electromagnetic waves without the need for a medium.
Mechanism: Emission of infrared radiation from the surface of an object.
Examples: Heat from the sun reaching the Earth, heat from a fireplace.
Factors: Surface temperature, emissivity of the material, surface area, and the temperature of surrounding objects.