Wyniki 1-1 spośród 1 dla zapytania: authorDesc:"Sergey M. MATVIENKO"

Improving the way of determination substances thermal physical characteristics by direct heating thermistor method DOI:10.15199/48.2019.04.21

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When determining the coefficient of thermal conductivity by direct heating thermistor method there is an error of calculation, the value of which depends on the method by determining the coefficient of thermal conductivity. This problem can be solved by optimal and accurate determination of the calibration coefficients used in the calculations. In this work has been carried out the research of errors occurring in the application of known methods and proposed a new method for determining the thermal conductivity of substances to improve the accuracy of their measurement. Formulation of the problem The purpose of this work is to research the error of measurement for existing methods for the determination of thermophysical characteristics (TPC) measured by the direct heating thermistor method to increase the measurement accuracy by choosing the optimal method of mathematical calculations for the thermal conductivity of substances under study by measuring the temperature of the thermistor's heating during it`s heating under the action of electric current. Main research material The essence of the direct heating thermistor method is to use the phenomenon of it`s self-heating due to flow through it of electric current. The temperature of the selfheating thermistor will depend on the environment in which it is located, that is, from the TPC of the research substance, which the thermistor has a thermal contact with. For an ideal model of a thermistor sensor in the ball form with radius r with ideal thermal conductivity, provided that the thermistor is surrounded by the research material, the coefficient of thermal conductivity is determined by the formula [1]: (1) r T Pt     4 where λ - thermal conductivity coefficient of the investigated material, W/(m·K); Pt - thermistor power, W; r - radius of the head of the thermistor, m; ΔT - temperature of the thermistor, оi[...]

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