Introduction And Principle Of Insulation Materials
Insulation material is divided into porous materials, heat reflective materials and vacuum materials three categories. The former uses the pores contained in the material itself to insulate because the air or inert gas in the voids has a low thermal conductivity, such as foams, fibrous materials, etc .; the heat-reflective material has a high reflection coefficient that reflects heat Gold, silver, nickel, aluminum foil or metallized polyester, polyimide film and the like.
Vacuum insulation material is the use of internal vacuum material to achieve the barrier convection to heat insulation. Aerospace industry on the use of insulation materials, the weight and volume requirements are more demanding, often also requires it both sound insulation, vibration, corrosion and other properties. Various aircraft on the need for insulation materials are not the same. Aircraft cockpit and cockpit commonly used foam, ultra-fine glass wool, high silica cotton, vacuum insulation board to heat.Heat Insulation Materials
The head of the missile with the early insulation material is phenolic foam, with good temperature resistance of polyurethane foam applications, in turn a single insulation material for the development of sandwich structure. Missile instrument compartment insulation method is in the bulk of the skin coated with a layer of a few millimeters thick foam coating, at room temperature as an anti-corrosion coating, when the aerodynamic heating to 200 ° C or more, they even foam Heat insulation.Heat Insulation Materials
Artificial earth satellites are in high temperature, low temperature alternating environment, the use of high reflective properties of the multi-layer insulation materials, generally by dozens of layers of aluminum foil, aluminum polyester film, aluminum polyimide film composition. In addition, the development of surface insulation tile successfully solved the problem of heat insulation of the space shuttle, but also marks the higher level of development of thermal insulation materials.
Airgel felt is a new type of thermal insulation material, which is a nanometer pore size porous material, used for pipe insulation, equipment insulation, the material thermal conductivity at room temperature 0.018W / (K · m), low temperature to 0.009 W / (K · m).
Vacuum insulation board is the latest insulation materials, popular in foreign countries, and more for the home appliance industry, this material has a very low thermal conductivity of 0.004, so the effect of energy saving on the above highlights. At present the domestic refrigerator refrigerated containers have been fully used this material. Naji insulation soft felt is a very strong thermal insulation properties of industrial insulation materials.
Heat transfer in the building heat exchange performance in three ways: conduction heat + convection heat <25%, radiant heat> 75%.Heat Insulation Materials
Summer tiles roof temperature increases, a large number of radiant heat into the room led to the temperature continued to rise, work and living environment very uncomfortable. Dike aluminum foil coil solar radiation absorption coefficient (normal total radiation emissivity) 0.07, very little heat of radiation. It is widely used in thermal insulation of roof and wall. Thermal energy transmission route (without insulation film): Sun - Infrared magnetic wave - Thermal impact of the tile to the temperature rise - the tile becomes a heat source to radiate heat - thermal impact of the cast - in - place roof to raise the temperature - Roofs become heat sources radiate heat - the indoor ambient temperature continues to rise
Thermal energy transmission line (plus insulation film): sun - infrared magnetic wave - thermal impact of the tile to the temperature rise - the tile becomes a heat source of heat radiation - thermal impact aluminum foil to surface temperature rise - aluminum foil emitter Low, low heat radiation - the room to maintain a comfortable ambient temperature.