Investigation of Novel Virtual Impactor Designs on the Aerodynamics of Material Flow in Aerosol Jet Printing (AJP)

Abstract

This study presents a computational investigation into how different exhaust configurations affect the internal flow characteristics and aerodynamics of a virtual impactor (VI) designed for use in aerosol jet printing systems. Four geometrical designs were evaluated using Computational Fluid Dynamics (CFD), each incorporating a unique exhaust layout configuration, including a single perpendicular exhaust, dual perpendicular exhausts, dual parallel exhausts, and an annular exhaust configuration. The analysis focused on major aerodynamic parameters, including velocity fields, pressure profiles, turbulence characteristics, and recirculation behavior. Velocity contours revealed consistent high-speed jet formation in all cases, with observable flow splitting and axisymmetric deflection into the separation chamber. Design 2 produced the most balanced and symmetric velocity transitions, while Design 3 displayed irregular gradients near the collector inlet. Streamline analysis indicated that Design 2 suppressed counter-circulation loops more effectively than the other designs. Pressure analysis showed that Design 1 consistently exhibited elevated static pressure in the collector region, which may contribute to improved particle retention but potentially reduce inertial focusing. In contrast, Design 4 featured lower collector pressure, favoring inertial separation but possibly increasing recirculation risk. Turbulent kinetic energy (TKE) and eddy viscosity distributions remained similar across all designs, with turbulence concentrated near the jet separation zone. These findings emphasize importance of exhaust port symmetry and distribution in controlling internal VI flow behavior. The results provide actionable insights for optimizing geometry to balance flow stability, pressure profiles, and inertial separation efficiency in high-resolution printed electronics applications.