Assessment of turbulence models for low turbulent natural convection heat transfer in rectangular enclosed cavity using OpenFOAM

Abstract

This research aimed to study two-equation turbulence models, for the simulation of low turbulent natural convection heat transfer, which happened in a rectangular enclosure. These models include k–ɛ, k–ω, RNG k–ɛ, k–ω SST and Realizable k–ɛ which are two-equation turbulence models in OpenFOAM. The simulation was carried out to compare against experiment in literatures which gave a Rayleigh number (Ra) of 1.58×109. The 3D cell structure by the 50×50×100 cells for the rectangular enclosure dimensions of 0.75 m (width)×0.75 m (height)×1.50 m (length) was modeled. It gave the large y+ of 30 but was still in the initial sub-layer. It was found that the k–ω model provided the best prediction of turbulent natural convection heat transfer. The standard k and ω wall functions were carried out to simulate well with the k–ω model. It was good modeling technique which the fine cells were not necessary to define nearly enclosure walls.