Large-eddy simulation of thin film evaporation and condensation from a hot plate in enclosure: Second order statistics
Résumé
The archetypal case of a hot and wet plate surrounded by a cold and wet square enclosure is studied. Turbulent natural convection, the water evaporation/condensation, the heat exchange between the air and the enclosing solid bodies are simulated. The large-eddy simulation methodology is adopted in conjunction with a dynamic Lagrangian model for sub-grid scale viscosity and thermal-vapour diffusivities. Two statistical steady state simulations (maximum Ra = 5 × 10 8) and three transitory drying-process simulations are carried out by deactivating and activating the air-solid heat transfer, respectively. The present work extends the companion study of Cintolesi et al. [8], where first order statistics of the above mentioned cases were presented. Here, second order statistics are shown: first, the turbulent structures of the thermally uncoupled cases are analysed, along with the velocity root-mean square, the turbulent scalar fluxes and the turbulent kinetic energy budget. A few zones of negative production of turbulent kinetic energy are identified and discussed. The presence of splat and anti-splat events on the enclosure surface is detected and discussed. Subsequently, the evolution of the drying-process simulations is reported: the physical properties of the plate materials lead to different decays of the surface thermal fluctuations.
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