Thermal analysis of a nanofluid free jet impingement on a rotating disk using volume of fluid in combination with discrete modelling

Abstract

The objective of this research is to analyse the heat transfer characteristics of air/nanofluid jet cooling flow on a hot circular rotating disk and track the possible fate of nanoparticles. Computational methods are employed to initially solve the air and liquid multiphase flow in ANSYS Fluent 19.3 by considering the importance of surface tension between two phases through the volume of fluid model. Subsequently, the nanoparticles are injected through the nozzle into the jet liquid to calculate nanoparticles distribution via pre-defined user functions. The impacts of parameters such as nanoparticles volume fraction and disk rotation are evaluated. The patterns of the jet flow from inlet until steady-state condition shows that there exist six stages of fluid flow for a stationary hot disk, while splattering of droplets disappears when the disk starts rotating. In spite of the positive impact of nanoparticles for rotating disk, larger torque is required for higher nanofluid volume fraction to enhance heat transfer due to increase in viscosity. Also, the trend for heat transfer coefficient identifies five flow regions from the stagnation point to the edge of the rotating disk.