Investigation of particle deposition efficiency enhancement in turbulent duct air flow by surface ribs with hybrid-size ribs

Abstract

This study presents the particle deposition enhancement by hybrid-size and same-size surface ribs in turbulent air duct flows using computational fluid dynamics simulation. The Reynolds stress turbulence model with UDF corrections and discrete particle model were adopted to simulate the turbulent air flow fields and particle deposition behaviours, respectively. After numerical validation with the relative literature results, pure particle deposition enhancement ratios, flow drag increase, comprehensive deposition efficiency and deposition enhancement mechanisms were investigated and discussed in details. The findings showed that the hybrid-size ribs with small rib spacing have the best enhancement performance on particle deposition for small particles ( ${\tau }_p^{+}<1$ ). Considering the flow drag increase, the maximum deposition efficiency can reach 485 for 1 µm particles for the hybrid-size ribbed cases, while it is just 425 for the same-size ribbed case. Nevertheless, no obvious particle deposition enhancement can be found for large particles ( ${\tau }_p^{+}>1$ ) for all types of surface ribs. The hybrid-size surface ribs are more efficient compared with the same-size ribs, which can be applied in the air cleaning equipment to improve the aerosol particle removal performance.