Time:2017-07-31
Heat transfer, that is, heat transfer. Where there is a temperature difference, there must be a hot pass. According to the different heat transfer mechanism, there are three basic ways of heat transfer: heat conduction, convection and radiation. In a specific thermal equipment, there are often several ways of heat transfer at the same time, which constitutes a comprehensive heat transfer.
First, the heat, refers to the direct contact with the various parts of the body heat exchange phenomenon. As in an object, high-temperature heat will give low temperature heat transfer; the other is two objects contact, high temperature objects will heat to low temperature objects.
Second, convective heat transfer, in industrial production often through the flow of fluid to achieve the purpose of transferring heat, this relative displacement caused by the flow of particles caused by heat transfer, known as convection heat transfer. There are two reasons for convective heat transfer, one is the natural convection, the temperature of the fluid is different, it will cause the density of different, causing the light floating, heavy sink; the second is forced convection, in the fluid System, due to the role of the pump, fan or stirring force, so that the movement of fluid particles.
Third, radiation heat transfer, a phenomenon of energy transmitted by electromagnetic waves. Between high temperature objects and cryogenic objects, thermal energy can be emitted to each other in the form of electromagnetic waves, while also absorbing the energy of each other. This result is the high temperature object radiation heat transfer to low temperature objects. This heat transfer does not require any medium. Thermal radiation not only produces energy transfer, but also with the energy form of the conversion. That is, in the heat, the heat energy into radiant energy, in the form of electromagnetic waves to the space transfer, when encountered another object can absorb radiation energy, that is part or all of its absorption and into heat.