دانلود رایگان مقاله انگلیسی تاثیر اندازه ذرات بر روی ویسکوزیته نانوسیال - نشریه الزویر

ABSTRACT

Nanofluids are potential new generation heat transfer fluids, which have been investigated meticulously, in recent years. Thermophysical properties of these fluids have significant influence on their heat transfer characteristics. Viscosity is one of the most important thermophysical properties that depends on various parameters. Size of the particles used in nanofluids is one of these effecting parameters. In this work, experimental studies considering the particle size effect on the viscosity of the nanofluid have been reviewed. Firstly, comparison of nanofluid and surfactant type, production and measurement methods were considered. Viscosity results of selected studies were evaluated in view of the parameters such as particle size, temperature and concentration. Furthermore, effective viscosity models of nanofluids, which include particle size as a parameter were discussed. The results indicate that there is a discrepancy about the effect of particle size on the viscosity of nanofluids. Moreover, it is observed from the evaluated data that the relative viscosity variation can be almost 40% either upwards or downwards by only altering the particle size.

4. Concluding remarks

Nanofluid related studies keep growing exponentially for the last two decades. However, commercialized application of the subject so far is not common, and many attempts are still being made by the scientific community. Utilized nanofluids in the existing literature show varying viscosity results due to the production method, nanoparticle and base fluid pairing, surfactant and measurement method. One of the prominent parameters which influences the viscosity of nanofluids is the particle size. Nonetheless, the number of studies on the effect of particle size is inadequate.

In this review, papers focused systematically on the size effect on nanofluid viscosity have been considered. It has been observed that there are discrepancies between discussed studies on viscosity values for different particle sizes even when their nanoparticle concentrations are similar. It is also evident that, according to collected data, the relative viscosity can increase up to 40% [56] or decrease up to 37% [49] by merely altering the particle size for the same nanofluid samples.