Experimental Study of Solid Particle Deposition in 90° Ventilated Bends of Rectangular Cross Section with Turbulent Flow

Abstract

Nowadays, ventilation ducts, especially duct bends, play a significant role in filtering aerosol contaminant for the built environment. This article experimentally investigates practical averaged aerosol deposition in 90° ventilated bends of rectangular cross section by measuring particle concentration changes at bend inlet and outlet in steady state. The measured penetrations at Reynolds number Re = 17,900 and 35,600 are in good agreement with previously published data at small Stokes number, which justifies the effectiveness of the measurement process. Particle penetration decreases from approximately 100% for St = 5.2 × 10−4 particles to 64% for St = 0.55 particles in acrylic glass bends. For the particles of Stokes number larger than 0.089, particle penetration is much higher than that in previous studies. This behavior is believed to be caused by the consideration of particle rebounce from bend wall in the presence of centrifugal force. The changes in Reynolds number do not significantly alter the tr...