The microwave heat distribution is the distribution (allocation) of the heat release inside the microwave absorptive material irradiated with high intensive
microwaves
Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency rang ...
.
The pattern of microwave heat distribution depends on many physical parameters, which may include the
electromagnetic field
An electromagnetic field (also EM field or EMF) is a classical (i.e. non-quantum) field produced by (stationary or moving) electric charges. It is the field described by classical electrodynamics (a classical field theory) and is the classical c ...
, the
specific absorption rate Specific absorption rate (SAR) is a measure of the rate at which energy is absorbed per unit mass by a human body when exposed to a radio frequency (RF) electromagnetic field. It can also refer to absorption of other forms of energy by tissue, incl ...
and structure of the processed material, the geometrical dimensions of the processing cavity, etc.
Most of the industrial
microwave heating
Dielectric heating, also known as electronic heating, radio frequency heating, and high-frequency heating, is the process in which a radio frequency (RF) alternating electric field, or radio wave or microwave electromagnetic radiation heats a diel ...
applications need a uniform heat distribution.
For example, the uniformity of microwave heat distribution is key parameter in microwave food sterilization, due to the potential danger directly related to human health if the food has not been heated evenly up to desirable temperature for neutralization of possible
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
population.
There are many different methods for achieving uniform heat distribution inside the irradiated material. They may involve
computer simulation
Computer simulation is the process of mathematical modelling, performed on a computer, which is designed to predict the behaviour of, or the outcome of, a real-world or physical system. The reliability of some mathematical models can be dete ...
and different mechanical mechanisms such as turntables and stirrers.
The proper microwave energy pattern is necessary for attaining a uniform heat release.
See also
*
Susceptor
A susceptor is a material used for its ability to absorb electromagnetic energy and convert it to heat (which in some cases is re-emitted as infrared thermal radiation). The electromagnetic energy is typically radiofrequency or microwave radiation ...
br>
Electromagnetic-Temperature Control & Optimization of Microwave Thermal ProcessingA hybrid technique for computing the power distribution generated in a lossy medium during microwave heating
References
Microwave processing of Materials, National Research Council
Publication NMAB-473
Washington, DC, 1994
J. Chang, and M. Brodwin, “A new applicator for efficient uniform heating using a circular cylindrical geometry,â€
J. Microwave Power & Electromagnetic Energy
vol. 28, pp. 32–40, March 1993
External links
Electric and magnetic fields in matter