Simulation of Water Evaporation within Artificial grounds for Thermo-regulation of CITY

The global warming and the more extreme events related implies that cities will be concerned by Urban Heat Island (UHI) effect more often and more intensively. Pavements covers between 30% and 40% of city areas and are identified as having a strong effect on the UHI. Studies are showing that two major phenomenon can be used and then must be studied to reduce the effect of pavements on UHI : The albedo and the evaporation of water. The increase in albedo has a beneficial effect on the surface temperature of pavements but increases radiation on the vertical surfaces of the city. The present proposal focuses on the effect of water evaporation on UHI. Research on that topic is increasing in the recent years only few papers are available on the numerical simulation . However, the evaporation of porous media is a complex phenomenon by its geometry, its interactions between the matrix and fluids, the phase change etc. This complexity leads to macroscopic models with numerous parameters that are hard to obtain experimentally and to optimize. The aim of the present proposal is to develop a heat and mass numerical model that considers evaporation in a construction material. The model is based on a multiscale approach combining the ability of Lattice Bolzman Method at the pore scale and Finite Element at the macro scale. Experiments will be carried out at différent scales to validate the modelings. Finally experiments in simulated real life situation within the Sense City facility will be performed and simulated in order to validate the models.