Search results
Results From The WOW.Com Content Network
Heat transfer is classified into various mechanisms, such as thermal conduction, thermal convection, thermal radiation, and transfer of energy by phase changes. Engineers also consider the transfer of mass of differing chemical species (mass transfer in the form of advection), either cold or hot, to achieve heat transfer. While these mechanisms ...
The photon Hamiltonian for the quantized radiation field (second quantization) is [37] [38] = (+) =, († +), where e e and b e are the electric and magnetic fields of the EM radiation, ε o and μ o are the free-space permittivity and permeability, V is the interaction volume, ω ph,α is the photon angular frequency for the α mode and c α ...
Forced convection: when a fluid is forced to flow over the surface by an internal source such as fans, by stirring, and pumps, creating an artificially induced convection current. [3] In many real-life applications (e.g. heat losses at solar central receivers or cooling of photovoltaic panels), natural and forced convection occur at the same ...
Forced convection is a mechanism, or type of transport, in which fluid motion is generated by an external source (like a pump, fan, suction device, etc.). Alongside natural convection, thermal radiation, and thermal conduction it is one of the methods of heat transfer and allows significant amounts of heat energy to be transported very efficiently.
Thermal conduction is the diffusion of thermal energy (heat) within one material or between materials in contact. The higher temperature object has molecules with more kinetic energy; collisions between molecules distributes this kinetic energy until an object has the same kinetic energy throughout.
Convection, especially Rayleigh–Bénard convection, where the convecting fluid is contained by two rigid horizontal plates, is a convenient example of a pattern-forming system. When heat is fed into the system from one direction (usually below), at small values it merely diffuses ( conducts ) from below upward, without causing fluid flow.
Earth heat transport occurs by conduction, mantle convection, hydrothermal convection, and volcanic advection. [15] Earth's internal heat flow to the surface is thought to be 80% due to mantle convection, with the remaining heat mostly originating in the Earth's crust, [16] with about 1% due to volcanic activity, earthquakes, and mountain ...
Oil heaters transfer heat by convection and radiation. [4] They can silently heat larger rooms, but take longer to heat up. Like infrared models, they lack a fan, but circulate heat according to a room's air patterns, which is why it may take longer for a user to discern a difference in temperature.