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The thermal conductivity of heat transfer nanofluids has been determined to increase by 10%, when containing metal oxide nanoparticles and carbon nanotubes. The fluid viscosity of the nanofluids is relatively the same as water, and therefore cannot not account for the increase in thermal conductivity. However, the fashion in which the metal oxide particles conglomerate within the fluid could be a potential explanation for the spike. Results show that under the influence of a strong outside magnetic field, the thermal conductivity value decreases. The thermal conductivity value also decreases when the pH is shifted from 7 to 11.45.
In this study, soft sphere surfactants, with varying head group charges and alkyl chain lengths, were investigated for their effects on the thermal conductivity, rheology, density, contact angle and refractive index of nanofluids. It was noted that the thermal conductivity of the ionic surfactant micelles follows the effective medium theory of poor thermal conductance, with interfacial resistance towards infinity. It was also determined that the longer the alkyl chains on the nonionic surfactant micelles, the lower the thermal conductance at lower concentration and higher interface tensions. The adsorbed moieties were found to enhance the stability of the nanoparticles in the base fluid. The orientation of the cylinders and their aspect ratios are key to the thermal conductivity enhancement within the nanofluids, as cylinders with a high aspect ratio and an organized orientation, have an enhanced thermal conductivity. With the results observed, it was determined that these nanofluids may be useful for thermal management.
The field of nanofluids is relatively new, however researchers in this article aimed to research their thermal conductivity and dispersion behaviours. A nanofluid consists of free-floating, solid nanoparticles suspended in a base fluid. Specifically, Al2O3-H2O nanofluids were investigated in this study. Using a thermal constants analyzer, the thermal conductivities of various modifications of nanofluids were measured. Research concluded that pH and concentrations of SDBS dispersants have a great impact on the thermal conductivity of the nanofluid. The nanofluid had a considerably higher thermal conductivity than the base fluid itself, and with a weight fraction of 0.0015 (0.15%) of Al2O3, the thermal conductivity increased by 10%.
Thermal conductivity of heating and cooling fluids with added nanoparticles dubbed ‘nanofluids’ are used as potential to improve the efficiency of heat transfer fluids using a thermal constants analyser. The Thermal conductivity enhancements of Cu-H2O nanofluids are dependent on the weight fraction of nanoparticles, pH values and sodium dodecylbenzenesulfonate (SDBS) surfactant concentration of nano-suspensions. Combining both the pH and chemical surfactant is recommended to improve the thermal conductivity for practical applications of nanofluid. Results showed that the use of Cu nanoparticles will significantly enhance the thermal conductivity with the highest observed enhancement of 10.7%.
Coolers and thermal mugs play vital roles in many of our lives. Understanding the science behind insulation and the different types of materials used to make these products can help you make informed decisions when selecting your next purchase. Choosing the right thermal mug or cooler for your needs is extremely important for making a purchase...
