Modelling Turbulent Heat Transfer in a Natural Convection Flow

Abstract

In this paper a numerical study of a turbulent, natural convection problem is performed with a compressible Large-Eddy simulation. In a natural convection the fluid is accelerated by local den-sity differences and a resulting pressure gradient. Directly at the heated walls the temperature distribution is determinate by increasing temperature gradients. In the centre region convective mass exchange is dominant. Density changes due to temperature differences are considered in the numerical model by a compressible coupled model. The obtained numerical results of this study are compared to an analogue experimental setup. The fluid properties profiles, e.g. temperature and velocity, show an asymmetry which is caused by the non-Boussinesq effects of the fluid. The investigated Rayleigh number of this study lies at Ra = 1.58 × 10 9 .