lämpösiirron

Lämpösiirto refers to the transfer of thermal energy between physical systems. This process occurs when there is a temperature difference between the systems. Heat naturally flows from regions of higher temperature to regions of lower temperature. There are three primary mechanisms by which lämpösiirto takes place: conduction, convection, and radiation.

Conduction is the transfer of heat through direct contact. In solids, this happens as vibrations of atoms or molecules are passed along. In fluids, conduction also occurs, though it is often less significant than convection.

Convection involves the transfer of heat through the movement of fluids, which can be liquids or gases. When a fluid is heated, it becomes less dense and rises, while cooler, denser fluid sinks. This creates currents that distribute heat throughout the fluid. Natural convection is driven by density differences, while forced convection occurs when an external force, like a fan or pump, moves the fluid.

Radiation is the transfer of heat through electromagnetic waves, such as infrared radiation. Unlike conduction and convection, radiation does not require a medium to transfer heat. This is how the Sun's heat reaches Earth through the vacuum of space. All objects with a temperature above absolute zero emit thermal radiation. The rate of heat transfer by radiation depends on the temperature and surface properties of the objects involved. Understanding lämpösiirto is crucial in many fields, including engineering, physics, and meteorology.