Study on heat and mass transfer characteristics of unsaturated porous media under continuous wave laser irradiation

Using laser irradiation to remove contaminants from soil is an emerging soil remediation method. The model used in this paper is based on local thermal non-equilibrium, using a carrier gas to simulate the recovery of contaminant gases. Numerical simulations are employed to study the temperature field, the evaporation and condensation of moisture, and the transport of gases within the soil under laser irradiation. The results show that continuous wave laser irradiation can rapidly bring both the gas and solid temperatures in unsaturated porous media to conditions suitable for separating most organic contaminants from the soil. Within the effective influence range of the laser, the phase change of water and the gas's transport speed are enhanced. This model can provide a theoretical basis for laser soil remediation or the interaction between lasers and unsaturated porous media.