Complete breakup of liquids into ultrafine droplets by grid turbulence

Ultrafine droplets play an important role in materials processing and nanotechnology, with crucial applications in nanoparticle preparation, molecular spraying, water evaporation, nanodrug delivery, nano-printing/coating, among numerous others. While the potential of turbulent gas flow to enhance liquid breakup is acknowledged, the construction of turbulence-driven atomizers for generating ultrafine droplets remains a significant challenge. Herein, we report the innovation of grid-turbulence atomization (GTA), which employed a rotating mesh to deliver liquid and an air knife to spray ultrafine droplets. The airflow across the mesh transitions from laminar to grid-turbulence, leading to complete liquid breakup with three-stages: bag formation, stretching, and turbulence-induced breakup. Ultrafine water droplets with a 4.8 µm Sauter mean diameter have been achieved through GTA . The GTA system demonstrates versatility in atomizing various liquids including those with high viscosities of ~ 1000 cP. We further achieved high-quality production of ultrafine powders including milk, coffee, sugar, polymers, and ceramics, based on the combination of GTA and spray-drying. Our strategic methodology establishes pivotal link between turbulence characteristics and materials processing, influencing a wide range of applications and sparking further innovation in the field.