In this work, the laminar convective heat transfer performance and the pressure drop of water-based nanofluids containing Al2O3, TiO2 and SiO2 nanoparticles flowing through a straight circular tube were experimentally...In this work, the laminar convective heat transfer performance and the pressure drop of water-based nanofluids containing Al2O3, TiO2 and SiO2 nanoparticles flowing through a straight circular tube were experimentally investigated. The experimental results showed that addition of small amounts of nano-sized Al2O3 and TiO2 particles to de-ionized water increased heat transfer coefficients considerably, while the SiO2 nanofluids showed the opposite behavior attracting the authors' interests. An average of 16% and 8.2% increase in heat transfer coefficient were observed with the average of 28% and 15% penalty in pressure drop for Al2O3 and TiO2 nanofluids.展开更多
Nanofluid is a suspension of nanoparticles(solid particles with diameters below 100 nm)in a conventional base fluid with significantly improved heat transfer characteristics compared to the original fluid.The heat tra...Nanofluid is a suspension of nanoparticles(solid particles with diameters below 100 nm)in a conventional base fluid with significantly improved heat transfer characteristics compared to the original fluid.The heat transfer coefficient is a quantitative characteristic of the convective heat transfer.The purpose of this paper is to study the effect of the nanoparticle size(diameter)on the heat transfer coefficient of forced convective heat transfer of nanofluid in the fully developed laminar region of a horizontal tube.Using thermal conductivity model which is a function of the nanoparticle size,flow of a nanofluid(water+Al2O3)in a circular tube submitted to a constant wall temperature is numerically investigated with two particle sizes of 11 nm and 47 nm.The calculated results show that the nanoparticle size does not significantly affect the heat transfer coefficient,however,the heat transfer coefficient decreases as the particle size increases.展开更多
文摘In this work, the laminar convective heat transfer performance and the pressure drop of water-based nanofluids containing Al2O3, TiO2 and SiO2 nanoparticles flowing through a straight circular tube were experimentally investigated. The experimental results showed that addition of small amounts of nano-sized Al2O3 and TiO2 particles to de-ionized water increased heat transfer coefficients considerably, while the SiO2 nanofluids showed the opposite behavior attracting the authors' interests. An average of 16% and 8.2% increase in heat transfer coefficient were observed with the average of 28% and 15% penalty in pressure drop for Al2O3 and TiO2 nanofluids.
文摘Nanofluid is a suspension of nanoparticles(solid particles with diameters below 100 nm)in a conventional base fluid with significantly improved heat transfer characteristics compared to the original fluid.The heat transfer coefficient is a quantitative characteristic of the convective heat transfer.The purpose of this paper is to study the effect of the nanoparticle size(diameter)on the heat transfer coefficient of forced convective heat transfer of nanofluid in the fully developed laminar region of a horizontal tube.Using thermal conductivity model which is a function of the nanoparticle size,flow of a nanofluid(water+Al2O3)in a circular tube submitted to a constant wall temperature is numerically investigated with two particle sizes of 11 nm and 47 nm.The calculated results show that the nanoparticle size does not significantly affect the heat transfer coefficient,however,the heat transfer coefficient decreases as the particle size increases.
