STUDYING THE THERMAL CONDUCTIVITY OF MATERIALS

Аннотация

The article is devoted to the determination of the coefficient of thermal conductivity of materials by the method of continuous heat flow. Two types of materials were tested in the experiment: textolite and fluoroplast, which are both heat-insulating and antifriction. The experiment was conducted at the department of "Fundamentals of mechanics and engineering graphics" of the Tashkent institute of chemical technology on a standard laboratory stand. The results oftheexperiment are presented intheform ofsummary tables and a graph. Keywords:thermal conductivity, coefficient of thermal conductivity, heat flow, temperature gradient. 1. Introduction. The thermal conductivity of materials in the construction of modern structures is essential and important, since comfort and warmth in the living room will depend on which materials were chosen as construction materials. Currently, basalt fiber slabs produced in Uzbekistan, among others, are beginning to be used everywhere in Tashkent during the construction and reconstructionof residential premises [1–9]. In this regard, we consider it necessary and expedient to conduct a comprehensive study to determine their thermal conductivity in laboratory or production conditions before manufacturing and installingsuch buildinginsulationmaterials. 2. Methods ofresearch. To conduct experiments to determine the thermal conductivity coefficient of various materials, the department of "Fundamentals of mechanics and engineering graphics" has a corresponding experimental installation. On this type of equipment, studies can be carried out to determine the temperature gradient of various solid materials of round shape and limited thickness. This experimental equipment in the fields of science: thermal engineering and hydraulics, is manufactured by"Zarnitsa" in the Russian Federation (Kazan). Similar laboratory equipment inthis area ismanufactured in Germany (Hamburg) byGUNT[10–14]. This article provides a methodology for conducting a study on the thermal conductivity of samples made of textolite and fluoroplast. These materials are widely used both in general mechanical engineering and intheconstruction ofvarious structures. Recall that the thermal conductivity of materials is the ability of a material body to transfer heat from its more heated parts to less heated ones through the chaotic movement of particles. Consider a layer of a solid substance with a temperature of T enclosed between two 0 parallel plates located at a distance of ∆h from each other. Let the temperature of the lower page328 INTERNATIONAL JOURNAL OF ARTIFICIAL INTELLIGENCE ISSN:2692-5206,ImpactFactor:12,23 AmericanAcademicpublishers,volume05,issue04,2025 Journal: https://www.academicpublishers.org/journals/index.php/ijai plate rise instantly from T to T at time =0, which does not change at subsequent times. As a 0 1 result, the temperature profile inside the layer begins to change over time and, at sufficiently high temperatures, a stationary linear temperature distribution is established. In stationary conditions, to maintain the temperature difference (temperature gradient) ∆T=T –T , a constant 1 0 heat flowQis required. For sufficiently smallvalues of∆T, the ratio is valid: (1) Q ΔT = λ∙ According to expression (1), the rate of heat transfer through a unit surface area of the F ∆h layer F is proportional to the temperature difference at a distance of ∆h. The coefficient of proportionalityis called thecoefficient of thermal conductivity ofthematerial[15–18]. Equation (1) is also valid in cases where the space between the plates is filled not only with a solid, but also with a liquid or gas, provided that there is no convection and radiation. Thus, thisratio describes theprocess of thermal conductivity in solids,liquidsand gases. If the local rate of heat transfer through a unit of the layer surface (heat flux density) in the positive direction of the "y" axis is denoted by q , then at ∆h  0 the ratio (1) takes the y form: (2) dT qy =−λ∙ This equation is a one-dimensional formudlaytion of Fourier's law of thermal conductivity. It is valid if the temperature depends on only one "y" coordinate. Thus, the following formulation can be given to the law of thermal conductivity: the density of the heat flux due to thermal conductivity is proportional to the temperature gradient. The minus sign in equation (2) means that heat is spreading in thedirection of decreasing temperature. When experimentally determining the coefficient of thermal conductivity, as a rule, they strive to create a one-dimensional temperature field. So, in relation to the one-dimensional temperature field of flat, cylindrical and spherical layers under boundary conditions of the first kind,theequation for determiningthe thermal conductivity coefficient looks likethis: (3) K∙Q λ = where: Q is the heat flux (in W); t 1 &t1t 2−arte2 the temperatures of the outer and inner surface of the layer (ºC); K is a coefficient depending on the shape and size o