Large Eddy simulations of particulate flows inside a square differentially heated cavity at Rayleigh numbers up to 1011

The Differentially Heated Cavity (DHC) has often served as a suitable geometric model for naturally driven particulate flows inside closed volumes. While providing deep insights of the flow dynamics, 3D DNS or 3D LES simulations of DHC flows are very time-consuming and their potential extension to higher Rayleigh (Ra) numbers typical of room dimensions is problematic. In this study, therefore, a 2D-LES Euler-Lagrange approach is used to predict turbulent particle transport in a DHC. We first validate our predictions against a 2D DNS database at Ra 10(9) and 10(10) with particles having diameters greater than 15 mu m. We show that our LES results are in very agreement with the DNS data. In a second step, we extend our simulations to a fully turbulent Ra number 10(11) and particle diameters between 0.5 and 10 m. Details are provided on the particle deposition locations and airborne concentration decay rate with time. We show in particular that as the flow becomes more turbulent, the particle settling rates approach those predicted by the simple stirred settling model. (C) 2018 Elsevier B.V. All rights reserved.