Flow Topology and Particle Clearance in an Inkjet Printing Cleanroom Chamber by Immersed Boundary Method

Abstract

Abstract. Contamination control in inkjet printing cleanrooms is critical yet challenging due to the transient airflow disturbances caused by moving equipment. This study examines how exhaust geometry and suction momentum govern flow topology and particle clearance in such dynamic environments. A scalable computational framework is employed, combining a sharp-interface immersed boundary method (IBM) on a block-structured Cartesian grid with implicit large-eddy simulation (ILES) and a two-way coupled particle-source-in (PSI)-cell particle model. Seven ventilation configurations are simulated, independently varying exhaust aperture, exhaust velocity, and supply jet speed. Performance is quantified by end-of-cycle room balances (retention, removal, and escape ratios) and by a substrate-attached “critical zone” metric. Phase-resolved analysis links particle transport to specific flow structures, including capture layers, recirculation cells, and bypass paths. Results demonstrate that exhaust-side design is dominant: enlarging the outlet or increasing suction establishes a coherent capture layer that eliminates bed-top recirculation, reducing outward particle escape to approximately 1% and reducing critical-zone residue to near zero. In contrast, increasing supply jet velocity enhances impingement and lateral entrainment, raising outward escape to 16–17% without improving clearance. The study reveals the mechanisms controlling dilute, drag-dominated particles and provides a transferable, nondimensional protocol for chamber-scale ventilation design.