Validation of interphase interactions and isoAdvection implementation in a novel three-phase solver for nanofluid atomization

Nanofluids are widely applied in spray cooling, combustion, and coating processes, where nanoparticle dispersion modifies base fluid rheology and influences atomization behavior. Accurate modeling requires computational fluid dynamics (CFD) approaches that capture gas–liquid interactions, nanoparticle transport, and sub-grid effects including interphase momentum exchange, particle collisions, and Brownian motion. This study presents a novel three-phase solver developed in OpenFOAM based on multiphase mixture theory, incorporating the volume of fluid (VOF) method enhanced with isoAdvection for sharp interface reconstruction, adaptive mesh refinement (AMR) for high-resolution atomization, and closures for gravity, buoyancy, centrifugal forces, turbulent and shear-induced diffusion, van der Waals forces, and particle collisions. Nanoparticle rheology is modeled via kinetic theory. Validation was conducted in two stages. Sedimentation simulations for nanoparticle mass fractions of 1–7 wt. % predicted base fluid–nanofluid (B-N) interface and sediment height with maximum relative errors of 2.03% and 3.06%, respectively, and experimental relative standard deviations below 0.93% (B-N interface) and 3.87% (sediment height). Water primary atomization simulations benchmarked the isoAdvection-based solver against the standard OpenFOAM interIsoFoam solver and a multidimensional universal limiter for explicit solution (MULES)-based solver. Key performance parameters, including spray cone angle, liquid film thickness, and breakup length, were accurately captured, with maximum errors of 3.98% (isoAdvection) and 3.40% (interIsoFoam), outperforming MULES (7.79%). Overall, the developed solver demonstrates robust, quantitative agreement with experiments, accurately capturing nanoparticle transport, sedimentation dynamics, and primary atomization features in free-surface nanofluid flows under atmospheric and isothermal conditions.