Heat transfer and friction of rough ducts carrying gas flow with variable physical properties

Vilemas, Jurgis; Šimonis, Vytautas

doi:10.1016/0017-9310(85)90008-0

Cited by 30 publications

(2 citation statements)

References 5 publications

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“…A micro-structured surface on a smooth duct would increase the pressure differential, resulting in the increase of pumping power in air cleaners. The efficiency index η is defined by equation (32) 14,18,40 where Vdrough and Vdsmooth are the particle deposition velocity of a semi-circular micro-structured surface and smooth surface, respectively, and Fdrough and Fdsmooth are flow drag for a semi-circular micro-structured surface and smooth surface respectively. The pressure differential for different non-dimensional ratios of semi-circular structured surfaces were calculated as 24.37 Pa ( α = 3), 28.21 Pa ( α = 4), 30.83 Pa ( α = 5), 34.16 Pa ( α = 6) and 25.93 Pa ( α = 10).…”

Section: Resultsmentioning

confidence: 99%

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Enhancement of submicron particle deposition on a semi-circular surface in turbulent flow

Leung

et al. 2019

Indoor and Built Environment

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Air pollution due to suspended particles in the built environment threatens people’s health. The collection of submicron particles using air cleaners is especially difficult due to their tiny sizes. Surface patterned structures can enhance submicron particle deposition, thus improving the performance of an air cleaner. In this study, a semi-circular micro-structured surface was designed and optimized by considering particle deposition enhancement and reduction of pressure differential. The maximum efficiency ratio at the pitch-to-height ratio ([Formula: see text]) of 3 reached 1137 for the 1 µm particles but only 3.4 for 0.01 µm particles. The main mechanism of enhancing submicron particle deposition depends on the capture of the recirculation wake induced by semi-circular structures and entrainments of large turbulence kinetic energy to the near-wall regions. Submicron particles was observed to deposit between cavities on the semi-circular surface at a small [Formula: see text]. This study shows that surface patterned structures in the semi-circular shape at small [Formula: see text] can enhance the submicron deposition efficiency, thus providing a possible approach to improve the overall efficiency of air cleaners.

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Section: Resultsmentioning

confidence: 99%

“…A micro-structured surface on a smooth duct would increase the pressure differential, resulting in the increase of pumping power in air cleaners. The efficiency index g is defined by equation (32) 14,18,40 g…”

Section: Particle Deposition Velocity and Overall Efficiencymentioning

confidence: 99%