Assessment of the influence of the structural characteristics of granular systems of microsilicon on the properties of thermal insulation materials

Abstract

The article discusses experimental studies of the size and shape of structured particles of microsilica small angle x-ray scattering method and a photophonon theoretical description of the heat transfer process in complex heterogeneous structures to assessment of the structural characteristics of granular systems for the properties of thermal insulating materials. The mechanism of heat transfer in granular, porous systems is quite complex, since heat exchange occurs in a material consisting of two phases (solid and gas) and at the phase boundary. Heat transfer in liquid thermal insulation coatings can be carried out from one solid particle to another. In this case, the thermal conductivity will depend on: the chemical and elemental composition of the material; particle granulometry; surface topology - the presence of inhomogeneities, defects on the surface; the number of touches and the contact area between the particles. The heat transfer of gas in the pores is carried out when gas molecules collide. Thermal conductivity will be determined by the ratio of the free path of molecules and linear pore sizes, temperature and dynamic viscosity of the gas phase, the nature of the interaction of gas molecules with the solid phase. Heat transfer by radiation depends on the nature of the particles, the dielectric, magnetic permeability and the degree of blackness of the particle surface. Based on the analysis of possible mechanisms of heat transfer in granular systems, it can be argued that the effective thermal conductivity of the system depends, all other things being equal, on the structure of the pore space of granular materials, topology and the number of particle touches. Considering idealized models of the structure of granular materials in the form of ordered folds of perfectly smooth balls, we can obtain several variants of structures: with tetrahedral; hexagonal; cubic packing of balls.

Digitalization of the Astrakhan-Mangyshlak Main Water Pipeline

“…To update the initial data, the following information was used (Zhapbasbayev et al, 2021;Besimbayeva et al, 2023;Bekibayev et al, 2023;Beisembetov et al, 2020;Sangulova et al, 2022;Bekibayev et al, 2022): pipeline profiles; pipe parameters; list and location of stations on the linear part; list and location of measuring units on the linear part; list and location of various taps on the linear part; list and location of pump units in stations. passport characteristics of pumps and electric motors; physical water parameters (including rheological properties); water pipeline setting and protection maps; electric power tariffs.…”

Granular materials based on expanded sands and their production waste

“…Lightweight concretes based on porous aggregates, compared to cellular concretes, have increased strength, lower shrinkage and creep, which expand the scope of their application [ [1], [2], [3], [4], [5]]. The structure of lightweight concretes based on porous aggregates is mainly controlled by the aggregate.…”