Understanding the Hydrodynamic and Mass Transfer Performance of Newtonian and Non-Newtonian Twin-Liquid Film Flow

High-viscosity substances and systems are widespread in modern chemical engineering. The twin-liquid film, which combines a wall-bounded film supported by a solid wall and a confined-free film through the opening window, provides an effective way to enhance the interfacial heat and mass transfer of high-viscosity non-Newtonian fluid as well as Newtonian fluid. The average thickness, velocity, and pressure differences of the twin-liquid film are correlated with the effective viscosity (μeff) and effective Reynolds number(Reeff) unified regardless of fluid rheology. The local differences in the film thickness and velocity between the Newtonian and non-Newtonian twin-liquid films increase with window length, plate thickness, and μeff. When the diffusion coefficient is inversely proportional to viscosity, the stretching and contraction of the confined-free film with shear-thinning fluid not only boost convective mass transfer but also amplify diffusion, synergistically increasing the mass transfer rate by 5.5 times compared to the solid plate. Twin-liquid films provide a cost-effective approach to enhancing heat and mass transfer efficiency in high-viscosity non-Newtonian systems, such as ionic liquids and nanofluids.