Model of a cylindrical contact with a plane substrate and calculation of the effective thermal conductivity of a nano thread

The paper presents a model of cylindrical contact with flat substrate of nano tube system, liquids, and on its basis the effective thermal conductivity of studied nano liquids has been calculated depending on temperature at atmospheric pressure. It has been shown that heat transfer can take place only through the isthmus between the materials, i.e. such heat transfer exists between two contacting particles in close-packed nanoparticle structures. The maximum value of the gap between nano wire and the substrate is D / 2, i.e. the gap is comparable to the mean free path of air molecules. In some cases, gas or liquid may be present inside the gap between the nano structure and substrate. Calculations show that thermal resistance of air in gap is much higher than in the purely diffusion case, i.e. for nano scale geometries, the thermal boundary resistance between a liquid and a solid can be decisive. Analysis of the results of experimental-theoretical determination of thermal conductivity coefficient of gaseous ethers showed that with an increase in temperature, the effective thermal conductivity coefficient increases linearly, except for gaseous diethyl ether. As a result of the experiment, gaseous diethyl ether decomposes. The results of calculating the effective thermal conductivity (nastenon and solvents) showed that it decreases with temperature increasing and the addition of nano wires increases the effective thermal conductivity of solvent. (author)