MICROWAVE METHOD FOR DETERMINING THERMOPHYSICAL CHARACTERISTICS OF MULTILAYER STRUCTURES AND PRODUCTS

摘要

FIELD: thermophysical measurements, construction heat engineering. ;SUBSTANCE: invention can be used for thermophysical measurements, in construction heat engineering and various industries. The essence of the invention consists in heating the surfaces of the outer layers of the investigated three-layer structure by an electromagnetic field of the microwave range, and the radiation frequency is determined by calculation according to the known relation to determine the attenuation of power (losses) in the direction of propagation of the electromagnetic wave of microwave radiation in the dielectric so that it is subjected to thermal action no more than two-thirds of the thickness of each of the outer layers of the structure. Then, the excess temperature on the surface of each of the outer layers is measured at two points located at distances x1 and x2 from the line of the electromagnetic effect, and, using the information obtained about the temperature measurements and the power of the microwave exposure, according to the obtained mathematical relationships, the thermophysical characteristics of the outer layers of the structure are determined. To determine the thermophysical characteristics of the inner layer, first, according to a known ratio, the frequency of the electromagnetic wave of the microwave range is determined by calculation, at which no more than 2-3 mm of the outer layer will be exposed to heat, the heat effect is carried out through the circular region. Heat supply is carried out until a heat flux appears on the opposite side of the three-layer structure. Then the values ​​of temperatures and heat flux, penetrating all three layers of the structure, are measured. Using the measured values, as well as the previously obtained values ​​of the thermophysical characteristics of the outer layers, with the help of mathematical dependences describing the temperature difference in each of the three layers, the sought thermophysical characteristics of the inner layer of the structure under study are determined.;EFFECT: invention is aimed at improving accuracy of determining the desired thermophysical characteristics of multilayer structures and products.;1 cl, 5 dwg