This proposal requests a medium-level allocation of computational time on high-performance computing (HPC) resources within the National Academic Infrastructure for Supercomputing in Sweden (NAISS). The computational resources will support numerically intensive research projects focused on complex gas-liquid systems. These systems include falling liquid films, bubbles and droplets, and liquid jets. The following research topics are targeted. Research on falling liquid films will examine solute supersaturation under evaporative conditions, including the formation and dynamics of crystals in the film and the mechanisms of crystal deposition that lead to fouling of heat transfer surfaces. We will also study the influence of non-Newtonian rheology, (shear-thinning, viscoplastic, and elastoviscoplastic behaviors), on film hydrodynamics, evaporation, thermodynamics, and fouling probability. Interactions between turbulent high-speed gas flows and falling films in evaporator tubes will be analyzed to understand and quantify the resulting pressure drop. Additionally, the effects of modified heat transfer surfaces on film hydro- and thermodynamics, evaporation rates, supersaturation/crystal dynamics and pressure drop will be explored for both Newtonian and non-Newtonian liquids. Liquid jet breakup in turbulent gas flows will be studied to understand and quantify droplet size distributions and breakup lengths, providing insight into atomization and spray processes. Condensation on droplets in steam will be investigated numerically to study heat and mass transfer processes. Another project will assess bubble behavior in non-Newtonian liquids. Here, we will examine rheological effects on bubble shapes, interfacial heat and mass transfer, and the hydrodynamic forces acting on the bubbles. We will also study movement and deposition of droplets in porous media, with an application design of fibrous microstructures of face masks. These projects rely on large-scale multiphase Direct Numerical Simulations (DNS) and interface-resolving multiphase solvers to capture coupled fluid, thermal, and solute dynamics. Advanced numerical methods (predominantly open-source) such as adaptive mesh refinement, volume-of-fluid, interface reconstruction, phase-change models, non-Newtonian rheology models and phase-specific transport solvers will be employed to resolve the multiscale physics. The proposed simulations will provide fundamental insights into fouling mechanisms, film rheology effects, pressure drop phenomena, multiphase heat/mass transfer, and liquid jet breakup, with applications in evaporators, heat exchangers, process/food engineering systems, and spray/heat treatment technologies. The activities are funded by the Swedish Research Council VR, Formas, Vinnova and the Swedish Energy Agency.