A CFD assessment for mixed convection of nanofluids for nuclear application

Abstract

Nanofluids application in nuclear systems have been intensively studied for the past few years since it has been found out that this type of fluids exhibit a substantially higher critical heat flux (CHF) compared to "clean" water. Most studies done in these field usually focus on heat transfer criteria of the nanofluid itself and its industrial application including nuclear systems. In vertical upward heating flow, the turbulent heat transfer can be deteriorated if it goes from forced to mixed convection regime or also known as deteriorated turbulent heat transfer (DTHT) regime. Hence, since nanofluids application is being considered in nuclear systems, it is quite interesting to study the mixed convection phenomenon in the nanofluids flow. To this end the current paper focuses on computational fluid dynamic (CFD) analysis of mixed convection flow of the nanofluids. The nanofluids selected for the study are the ones considered for applications related to nuclear systems. Three turbulent models; namely the low-Reynolds k-ε model, the v2-f model, and the recently developed Elliptical Blending k-ε model are first examined to find out the best model to be used in nanofluids study. The impact of particles concentration in nanofluids on the mixed convection phenomenon is also investigated. This numerical work can give insights and a better understanding of the mixed convection phenomenon in the case of nanofluids-based systems and set a basis for future experimental verification.