Simulation of liquid thin film evaporation and boiling on a heated hydrophilic microstructured surface by Lattice Boltzmann method

In this paper, a newly developed 3D thermal Lattice Boltzmann method (LBM), incorporating double distribution functions (DDF), pseudo-potential model and equation of state (EOS) of a real gas, is used to simulate dynamic evaporation along the vapor/liquid interface and boiling in the liquid thin film on a microstructured surface consisting of micro pillars. Simulations are conducted under constant heat fluxes for four solid hydrophilic surfaces with contact angles of 10[degrees], 23[degrees], 37[degrees] and 63[degrees] respectively. With increasing heat flux, it is found that the liquid thin film recedes gradually into the wick structure, with the lowest liquid level at the center of the heating area, to maintain a continuous liquid supply via capillary pumping. The receding of the liquid thin film can normally enhance evaporation heat transfer because it not only reduces the thermal conduction resistance of liquid thin films, but also elongates the evaporating liquid meniscus along the height direction of micro pillars.