Many people are not very clear about ceramic fiber cotton. They ignore some places that should be paid attention to, and can not give full play to all the properties of ceramic fiber cotton. Today, Xiaobian will discuss with you about ceramic fiber cotton again, hoping to help you.
The convective heat transfer of ceramic fiber cotton depends on the heat transfer of fluid medium. The heat transfer inside ceramic fiber cotton mostly ignores the convective heat transfer, because the temperature difference in the pore chamber inside the fiber is very small, the convective heat transfer is very small, and the air flow can hardly be formed in the pores with diameter less than 3.
When radiation heat transfer or convection heat transfer is more and more involved in the total heat transfer at high temperature, there is a minimum between ceramic fiber cotton and porosity and effective thermal conductivity. With the increase of temperature, this minimum value approaches to a smaller porosity. Therefore, an important practical speculation can be drawn, that is, the thermal insulation material has an optimal porosity, i.e. bulk density, at each service temperature, and its thermal insulation effect is the best in this optimal range. Porosity has a certain influence on the effective thermal conductivity, and the pressure of pore gas also affects the thermal conductivity.