Analysis of Properties and Peculiarities of Functioning of Highly Porous Insulating Materials Based on Basalt Fiber

The results of experimental study of properties and peculiarities of functioning of the porous heat-insulating materials, produced using the method for filtration deposition, are presented. It is shown that the thermal insulation efficiency of highly porous materials increases as the porosity and the wall thickness of heat-insulating constructions grow. It is found, that for each type of the heat-insulating material, there is a critical temperature above which the intensive shrinkage develops. A value of the permissible temperature of the hot wall is set for fillers made of basalt, quartz, and kaolin fibers. The mathematical model describing a stationary regime of heat transfer in highly porous heat-insulating materials with consideration for the Stefan-Boltzmann thermal radiation in the pore space is proposed. On the basis of experimental study, the empirical constant in the nonlinear equation of heat conduction is determined, which takes into account the multiple interaction of thermal radiation flows between adjacent fibers of the filler. The relationship for calculation of wall thickness of the heat-insulating construction using the desired temperature difference between the hot and cold walls is proposed.

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