Тип публикации: статья из журнала
Год издания: 2016
Идентификатор DOI: 10.1134/S1029959916030085
Ключевые слова: nanoparticles, nanofluid, viscosity, thermal conductivity, heat transfer coefficient, molecular dynamics method, laminar and turbulent flow regimes, heat transfer coefficient, laminar and turbulent flow regimes, molecular dynamics method, nanofluid, nanoparticles, thermal conductivity, viscosity, Alumina, Cooling systems, Heat exchangers, Heat transfer, Heat transfer coefficients, Laminar flow, Molecular dynamics, Nanoparticles, Particle size, Thermal conductivity, Thermal conductivity of liquids, Turbulent flow, Viscosity, Circular cross-sections, Heat exchange process, High thermal conductivity, Laminar and turbulent flow, Molecular dynamics methods, Nanofluids, Thermal conductivity coefficient, Viscosity coefficient, Nanofluidics
Аннотация: Nanofluids present a new type of dispersed fluids consisting of a carrier fluid and solid nanoparticles. Unusual properties of nanofluids, particularly high thermal conductivity, make them eminently suitable for many thermophysical applications, e.g., for cooling of equipment, designing of new heat energy transportation and production systems and so on. This requires a systematic study of heat exchange properties of nanofluids. The present paper contains the measurement results for the heat transfer coefficient of the laminar and turbulent flow of nanofluids on the basis of distilled water with silica, alumina and copper oxide particles in a minichannel with circular cross section. The maximum volume concentration of particles did not exceed 2%. The dependence of the heat transfer coefficient on the concentration and size of nanoparticles was studied. It is shown that the use of nanofluids allows a significant increase in the heat transfer coefficient as compared to that for water. However, the obtained result strongly depends on the regime of flow. The excess of the heat transfer coefficient in the laminar flow is only due to an increase in the thermal conductivity coefficient of nanofluid, while in the turbulent flow the obtained effect is due to the ratio between the viscosity and thermal conductivity of nanofluid. The viscosity and thermal conductivity of nanofluids depend on the volume concentration of nanoparticles as well as on their size and material and are not described by classical theories. That is why the literature data are diverse and contradictory; they do not actually take into account the influence of the mentioned factors (size and material of nanoparticles). It has been shown experimentally and by a molecular dynamics method that the nanofluid viscosity increases while the thermal conductivity decreases with the decreasing dispersed particle size. It is found experimentally for the first time that the nanofluid viscosity coefficient depends on the particle material. The higher is the density of particles, the higher is the thermal conductivity coefficient of nanofluid.
Журнал: PHYSICAL MESOMECHANICS
Выпуск журнала: Vol. 19, Is. 3
Номера страниц: 298-306
ISSN журнала: 10299599
Место издания: NEW YORK
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