ABOUT NATURAL INTERRELATION OF ELECTRICAL CONDUCTIVITY, THERMAL CONDUCTIVITY AND THERMAL STATES OF AGRO-ENGINEERING SYSTEM ELEMENTS
The quality of processing crop and livestock production depends on the maintenance of normal thermal modes of power plants. This involves the use of sensors for monitoring their thermal state. For this purpose, it was offered to use the relationship between the thermal conductivity and electrical conductivity of metals, known as Wiedemann-Franz ratio (law). The known solutions of the Wiedemann-Franz equation related to Lorentz number were considered. While searching expressions for the thermal conductivity, Debyes formula was supplemented with the equation reflecting the bond of heat flow rate density by thermal conductivity in the metal sample with a share of the heat flow rate density of its own radiation. The ratio to calculate Lorentz number of especially pure metals was obtained taking into account their volume heat capacity, the number of valence electrons per atom and the melting temperature based on the well-known expression for the electrical conductivity of the metal and the experimental data. A ratio useful both for the development of sensors for monitoring the thermal state of heat-stressed components and for assemblies of metal structures by measuring electrical resistivity of the metal during the operation was proposed.