Nanofluids in Cooling Systems and Their Efficiency

In the materials of the article, it is shown that based on multifactor analysis, the proposed models of nanofluids are taken into account in the base fluids; a collision between nanoparticles and molecules; nanoparticles that occur due to Brownian motion; thermal diffusion of nanoparticles and their interaction with molecules; formation of percolation trajectories with low heat capacity in a fluid; influence of interphase and boundary layers in the separation of the solid and fluid phases; the surface shell effect; thin nanolayers; particle clustering. The study of nanofluids comes down to determining their thermal conductivity coefficient. It is established that the obtained values of thermal conductivity coefficients, which are 10 times higher than usual, do not fit into the classical calculation schemes used to determine the heat transfer coefficients. For cavities of nanofluid cooling systems, the thermal resistances of heat transfer and thermal conductivity are fictitious in magnitude. This is due to the fact that in the cooling cavities, the driving force is the potential jumps between the layers of the nanofluid. We selected the materials for creating nanoliquids that will be used in the new design of the braking system. It is formed by Al2O3 particles enveloped by polymeric material FK-24A. The diameter of nanoparticles was 15, 35 and 80 m. An increase in particle size and concentration results in an increase in the thermal conductivity of the liquid. In place of nanoliquid and metal components contact, the electrical potential and intensity of the electric field of nanoliquid change, that is also described here. When the temperature of the nanofluid rises above 100 °C it may become an electrolyte. The use of nanofluids in lubrication of drawworks braking system reduces the wear of friction couples by ~ 20 % and increases the braking moment by about 13 %.