Radiation (emission)
There are 3 types of heat transfer: Convection is a transfer of heat by the movement of fluid, conduction is a transfer of heat via physical contact, and lastly radiation (emission) is a transfer of heat by an electromagnetic wave.
Radiation is a phenomenon in which heat energy transfers from a high-temperature surface of an object to a low-temperature surface of an object.
Analysis considering radiation by heat transfer in addition to convection and conduction analyses can be performed in scFLOW.
Fig 1 Surface temperature of a board and a part inside an enclosure
(Left: without radiation, Right: with radiation)
In scFLOW, VF and FLUX methods are available according to the analysis model and target.
VF method is a calculation method that calculates view factor (the proportion of radiation energy which is emitted from one face and reaches another face) of a part surface and accurately treats the exchange of radiation energy between part surfaces.
FLUX method enables to consider absorption and scattering of radiation energy in an area or consider the influence of radiation in a moving object analysis though at a slightly high computational cost.
Fig 2 Surface irradiation of thermal heat radiation [W/m2]
Fig 2 illustrates a radiation analysis by VF method. Radiation heat is passing through a lens and a surface radiation [W/m2] of the surface of an object is observed. Radiation energy from the heat source (one surface of a cuboid) passed through the lens (refractive index:1.6) is concentrated at the center of the screen. The energy can also be found radiating out to the wall and to the ground.
An object being heated by radiation heat from the rotating heater.
Surface irradiation of thermal heat radiation
This animation shows how an object is being heated by radiation heat emitted from a rotating heater. Since rotating heater needs to be modeled with moving elements, flux method which can be used in combination with moving element function is employed.
Fig 3 illustrates a contour plot of the surface temperature of the object and a vector plot of radiation heat flux. Radiation energy emitted from the heater reaches the surface of the object and a gradual rise in the temperature of the object’s surface can be observed.