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Influencing Factors Of Heat Insulation Materials

Jul 06, 2017

              Heat insulation material can block heat transfer materials, also known as thermal insulating materials. Traditional insulation materials, such as glass fiber, asbestos, rock wool, silicate, etc. new insulation materials, such as aerogel felt, vacuum plates.

Filling gas: In thermal insulation, most of the heat is transmitted from the gas in the pores. Therefore, the thermal conductivity of thermal insulation depends largely on the type of gas filled. If helium or hydrogen is filled in cryogenic engineering, it can be used as a level approximation, and the thermal conductivity of the thermal insulation is similar to that of these gases, because the thermal conductivity of helium and hydrogen is relatively large.Heat Insulation Materials

             Heat: thermal conductivity = heat diffusion coefficient x specific heat x density. Under the same thermal diffusivity and density conditions, the higher the heat conductivity, the greater the heat transfer coefficient. The specific heat of the thermal insulation is related to the amount of cold (or heat) required to calculate the adiabatic structure during cooling and heating. At low temperatures, the specific heat of all solids varies greatly. At ambient temperature and pressure, the quality of air does not exceed 5% of the thermal insulation, but as the temperature drops, the proportion of gas is growing. Therefore, this factor should be taken into account when calculating the insulating materials for working under atmospheric pressure. For the commonly used thermal insulation, the above factors are the most affected by the apparent density and humidity. Therefore, the apparent density of the material must be measured at the same time when determining the thermal conductivity of the material. As for the humidity, for most of the thermal insulation is preferable to the air relative humidity of 80% 85% when the material balance humidity as a reference state, should be as far as possible in this humidity conditions to determine the thermal conductivity of materials.Heat Insulation Materials

             Vacuum: There are three kinds of heat conduction modes: convection, conduction and radiation. Convection mode of heat conduction is the most important. The convection coefficient of thermal conductivity is greatly reduced by vacuum, and the principle is like a thermos. As the skeleton filler material may pass through conduction way conduction, therefore uses the low thermal conductivity glass fiber to do the skeleton. The exterior and the aluminum film packing bag are blocking the radiation. So the material is the least thermal conductivity.Heat Insulation Materials