Turbulent particle loss augmentation in a ventilation duct.

Particle loss augmentation in turbulent flow was studied experimentally. Experiments were performed in a I SO mm square ventilation duct. Small tracer particles of size ranging from 0.7-7.l μ.m were used to study deposition enhancement with streamwise-periodic disturbances mounted on one of the principal walls, under turbulent flow. A new and highly sensitive analytical technique was adopted to determine the spatial mass flux along the ribbed duct. On some surfaces, particle deposition enhancement as much as seven times higher than on .smooth surfaces was observed. Periodic averages of mass transfer coefficients for different particle sizes were evaluated. The friction factor was approximately three times the smooth duct value. Efficiency indexes, based on equal fan power, were determined for all particle sizes.