Optimizing Vertical Unidirectional Airflow in Cleanrooms: An Integrated Approach to Floor Perforation, Plenum, and Fan Filter Unit Configurations

Maintaining vertically unidirectional airflow in cleanrooms is crucial for achieving air cleanness and protecting occupants inside, from industrial semiconductor technicians to hospital surgeons and patients. This study investigates airflow inclination and develops optimization strategies for vertical unidirectional flow cleanrooms, with a focus on enhancing airflow verticality and uniformity to reduce airborne contamination. A new dimensionless parameter, K1, is introduced to quantify the impact of lower interlayer airflow velocity on cleanroom airflow inclination, thereby providing a practical metric for design optimization. Key influencing factors, including flooring perforated plate configurations, plenum heights, and FFU (Fan Filter Unit) layout rates, are systematically evaluated. The results indicate that lower perforation rates (e.g., 10%) significantly improve vertical airflow by reducing inclination angles to below 25°, with a non-uniform perforated plate arrangement proving essential to sustain airflow verticality. Moreover, non-uniform perforated plate configurations are particularly effective in designs with low plenum heights (below 1.3 m). In addition, FFU layout rates above 60% are found optimal to provide vertical airflow, consistently achieving inclination angles below 20°. Further changes in FFU layout rate show minor returns on airflow verticality. The study establishes clear design guidelines for airflow optimization and highlights the dual benefits of these configurations in safeguarding occupational health and controlling airborne contamination in cleanrooms.