New model of pressure drop for the foam trays with dynamic bubbling process analysis

Open-cell foams as the column tray are promising candidates for the purpose of process intensification in the distillation process. In this paper, the real foam porous structure is obtained based on Micro Computed Tomography (µ-CT), and the bubble formation process on pore-scale foam tray is discussed based on the VOF-CSF model (volume of fluid method-continuous surface force). The results show that the wettability (CA), superficial gas velocity (Ug), porous structure, and clear liquid layer height (HCL) all affect a crucial factor of the foam tray - the liquid holdup in the porous channels (LHPC). It determines the effective porosity, which in turn affects the bubbling frequency and pressure drop. Meanwhile, the evolutionary mechanism of instantaneous pressure drop is analyzed based on the flow patterns, force analysis and interfacial phenomena. Moreover, the new model to predict pressure drop is proposed based on LHPC, which shows good consistency with experiments.