ACCOUNTING FOR FEATURES OF A POROUS STRUCTURE IN CALCULATING THE THERMAL CONDUCTIVITY OF WET GAS-SILICATE MATERIALS

Abstract

The pore space of gas silicate materials, regardless of density, is represented by large pores formed as a result of gas formation and small capillary pores. When liquid moisture is absorbed, only capillary pores are filled. Large pores contain a vapor-air mixture. Taking into account such a bimodal pore size distribution, a two-stage method for calculating the thermal conductivity of a material is proposed. First, one should consider an inhomogeneous three-component system consisting of a solid skeleton, in the finely porous part of which there is gas and liquid moisture. Then, a binary system is taken into account, the first component of which is the mentioned three-component system, and the second one is isolated gas inclusions in large pores. The thermal conductivity of a three-component system was determined using dependencies built on the basis of the theory of generalized conductivity. The thermal conductivities of the ternary and binary systems were determined using dependencies constructed using the theory of generalized conductivity. It has been established that the results of calculating the thermal conductivity of gas silicate materials using the proposed method practically coincide with the experimental values ​​obtained. And the calculations performed without taking into account the bimodal pore size distribution give results that are significantly less than the experimental data.