METHOD OF MEASURING THERMAL CONDUCTIVITY COEFFICIENT OF HEAT-INSULATING MATERIAL Russian patent published in 2020 - IPC G01N25/18 

FIELD: measurement.

SUBSTANCE: invention relates to the field of thermal measurements, namely to the heat insulation coefficient of heat-insulating materials. Disclosed is a method of measuring heat conductivity coefficient of heat-insulating material, comprising closed volume with removable cover 2, made from panels of heat-insulating materials, coefficients of heat conductivity of which are known in advance, having surface area inside Si, with heater 3, air temperature sensors 4, fans 5 located inside. Heating of air in volume to equilibrium temperature Ti by supply of stabilized power W to heater to achieve thermal equilibrium due to heat exchange of air inside volume through its walls with ambient air, temperature of which is automatically maintained at a constant level Te by temperature sensors 6 throughout the entire measurement cycle. Measurement of equilibrium temperature Ti₁ first with cover from first material, which coincides with thickness of analyzed material, and then measuring equilibrium temperature Ti₂ after replacement of first cover by cover from analyzed material. Heat transfer coefficient is calculated in two steps. First stage consists in calculation by method of selecting parameter of total heat flow through all walls and cover of closed volume W₁ using the values of Te₁ and Ti₁ obtained at this stage, wherein the heat transfer surface area is selected to be the area of the inner surface of the closed volume Si, obtaining a substantially lower heat flow value W₁, then, by selecting parameter increasing Si, it is achieved that calculated value W₁ coincides with power of heater W, and new value of heat transfer area Seff is fixed. At the second stage of the measurement, the detachable cover is replaced with the sample of the analyzed material of the same thickness and after the thermal equilibrium is established, new values of Te₂ and Ti₂ are obtained, calculating total heat flow W₂ through all walls and cover of closed volume, but this time as area of heat transfer surface is selected area of heat transfer Seff, determined at first stage of measurement, wherein again using the parameter selection method, it is achieved that W₂ coincides with W, selecting for this time as a parameter value of the heat transfer coefficient K of the cover from the analyzed material, which, as a result, is the unknown value of thermal conductivity coefficient of heat-insulating materials.

EFFECT: reduced measurement error of heat transfer coefficient.

1 cl, 2 dwg