СНИЖЕНИЕ ТЕМПЕРАТУРЫ ГИЛЬЗЫ ЦИЛИНДРА ЗА СЧЁТ ПРИМЕНЕНИЯ ТЕПЛОНОСИТЕЛЯ С ВЫСОКОТЕПЛОПРОВОДНЫМИ НАНОЧАСТИЦАМИ МУЛЬТИГРАФЕНА

Abstract

The paper considers one of the promising ways to influence the heat transfer in the cooling system of a cylinder-piston group, which is to improve physical properties of coolants. It has been stated that the development of nanotechnology has recently made it possible to significantly increase the thermal conductivity coefficient of base coolant - an aqueous solution of ethylene glycol due to its modification by high-conductive solid multigraphene nanoparticles. The resulting stable two-phase suspensions based on the base coolant and particles of the solid phase are called nanofluids. To evaluate the increase in heat transfer at the “wall-coolant” boundary and the decrease of temperature of this wall when applying nanofluid in the engine cooling system as compared to the base fluid, an experimental setup was developed for simulating the flow of coolant in the annular channel of the cooling cavity of the cylinder liner and the conditions determining the heat transfer in its cooling cavity. As a result of conducting a series of experiments under similar test conditions, a significant increase in the heat transfer coefficient was found at the boundary of the “liner wall-liquid” due to the use of nanofluids with highly heat-conducting multigraphene nanoparticles compared to the base fluid. This led to a decrease in the temperature of the cylinder liner. Reducing the temperature of the heat-loaded engine parts allows to increase the reliability of the promising and forced diesel engines, to increase the degree of boosting at the average effective pressure while maintaining the permissible temperature level of the parts of the cylinder-piston group. Intensification of heat transfer at the “wall-liquid” interface contributes to an increase in the thermal efficiency of various heat exchangers as part of an internal combustion engine associated with the main circuit of the cooling system.