Investigation of efficient air pollutant removal using active flow control

Efficiency in maintaining indoor air quality is central to the operation of high-performance buildings. The purpose of this work was to investigate the effect of airflow velocities generated by a low-power annular, multi-orifice synthetic jet actuator (SJA) on the degradation rate of a model air pollutant, nitrogen dioxide (NO 2 ), by a photocatalytic surface. In this study, the active flow fields generated by the SJA were first characterized, and the effect of SJA-to-wall distance was analyzed as the airflow impinged on a wall of varying surface textures. Second, the impact of flow characteristics, namely surface velocity and velocity distribution, on the removal rates of NO 2 by the photocatalytic surface was investigated in a closed chamber. Results showed that a SJA-to-wall (L) distance of 315 mm had the greatest reduction (dampening) on peak airflow velocities. Also, the surface with the highest roughness used in this study resulted in increased turbulence at the wall surface. The use of the SJA enhanced the removal rate of NO 2 compared to passive (control) conditions. Increases in air velocity, however, did not monotonically enhance the removal rate of NO 2 . The highest removal rate ( k = 0.0013 min −1 ) was measured at L = 315 mm, where the highest velocity dampening was observed. It also corresponded to an average surface velocity of approximately 0.1 m/s across the photocatalytic surface.