Thermophysical characteristics of porous thermal insulation materials (PTM) aregenerally determined by the structure, size, type and shape of pores, as well as by theirmutual arrangement in the material. Thermal conductivity is one of the most importantamong these characteristics, is caused by different physical processes and can be reducedto three types: conduction, convection and radiation. Literature sources imply that thermalconductivity dependence is represented as an exponential function. These dependencies failto have a sufficiently clear and pronounced nature and do not allow developing an analyticalexpression to describe this function, especially at high values of material density. In our548 Hanna Koshlak, Anna Kaczanexperiments, the thermal conductivity coefficient was determined in the dry and sorptionhumidity states, not exceeding 20%. The thermal conductivity of porous thermal insulationmaterials was studied using an IT-λ-400 device. Cylindrical test specimens, 5 mm thick and15 mm in diameter, were placed in the device and heated to 800°C. Within this temperaturerange, the material thermal conductivity was determined according to the standard proce-dure described in the device operating instructions. The observed data were processed usingthe designed experiment approach. Thermal conductivity is considered as the target function(Y, W/(m K)). The experiment was conducted according to the program of the central com-posite rotatable second-order design by Box-Hunter. The factors, studied in the previousseries of experiments, are considered as controllable ones. Variable factors shall meet thesecriteria during experiment design process. 16 experiments were conducted at basic levelsand supplemented by another 10 experiments at star points.
Nov 6, 2023
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Koshlak, Hanna Pavlenko, Anatoliy
Hadi, Nizar Jawad Al-Hussain, Rand Kareem Abd
Kutnyi, Bohdan Pavlenko, Аnatoliy Koshlak, Hanna
Klembt , Daniel Meironke , Heiko