A numerical study on nanoparticles shape effects in modulating heat transfer in silver-water nanofluid over a polished rotating disk

Abstract

Investigations of mechanical and thermodynamic aspects related to flows induced by rotating disks are of paramount importance, given their widespread application in various industrial processes. Keeping this in mind, the present study examines the influences of nanoparticles shape on heat transfer for silver-water nanofluid flow over a polished rotating disk. The nanofluid's viscosity demonstrates dependence upon temperature and nanoparticles volume fraction, considering both the cylindrical and spherical type nanoparticles. The polished disk surface proposes velocity and thermal slip at the interface. The present mathematical model also accounts for heat generation/absorption along with the aforementioned aspects. Reduction in the governing system through 'similarity transformations is carried out. The resulting system of equations are solved numerically using the built-in numerical solver NDSolve in Mathematica. Outcomes reveal that the variations in viscosity due to temperature not only impact skin friction but also the Nusselt number for given flow. Another noteworthy result is that a polished rotating disk demonstrates reduced wear and tear attributed to higher skin friction, which can be further mitigated by enhancing the velocity slip parameter. Notably, this study uncovers different impacts of cylindrical and spherical nanoparticles, advancing the understanding of heat transfer and the mechanics of rotating disc flows. Cylindrical and spherical nanoparticles exhibit distinct behaviors within the flow. This cautions engineers to carefully select nanoparticles geometries to optimize heat transfer performance based on the specific requirements of their applications. Understanding these geometry-dependent effects is essential for designing efficient heat transfer systems.