The aim of this work is to analyse the flow in the high temperature solar receiver of the central tower power plant PEGASE. The flow is turbulent and submitted to a very high temperature gradient. We use the Thermal Large Eddy Simulation applied to the lowMach number equations in order to work on the turbulent flow in geometry of a biperiodic plane channel with temperature imposed to the wall. For this study, we realize simulations for two different turbulent Reynolds numbers (Re _taum = 180 and Re_tau m = 395) and for four temperature ratios (T2=T1 = 1, 1:04, 2 and 5). After the validation of the model, we realize a study on the thermal subgrid-scale modeling that conclude on the requirement to use a dynamic thermal subgrid-scale model for a flow with a high turbulent intensity and submitted to a very high temperature gradient. We analyse the impact of the temperature gradient on all the velocity and temperature profiles and on the energy spectra. The increase of the temperature gradient creates a dissymmetry of all the profiles. A relaminarisation on the hot side of the domain is visible. We note a new repartition of the fluctuations across the channel and a new repartition of the energy in function of the size of the scales. A creation of velocity and temperature fluctuations is also point up on the hot and the cold side. These effects are due to the cinematic viscosity variation (direct effect of the temperature) and to an interaction between the dynamic and the thermal fields.
