Capture of high-viscosity particles: utilizing swirling flow in the multi-layer square chamber

Abstract

Cooking oil fume (COF) contains a variety of high-viscosity particles with multiple diameters. For protecting the exhaust fan in range hood, these particles should be captured before they reach the fan blade. However, current particle filter component in range hood possesses either low capture efficiency or high flow resistance. This paper proposed a novel structure with multi-layer square chamber for the capture of high-viscosity particles in COF. The centrifugal effect of the swirling flow that generated in the chamber made the particles gradually moving towards the inner walls, thus increasing the possibility of particle trap. Orthogonal experiment based on CFD simulation was involved to explore the effect of the flow and structure factors. Discrete phase model (DPM) was chosen to track the trajectory of the particles moving in the chamber. The results indicated that with proper design, the capture efficiency of particles above 5 μm reached 95.0%, and particles above 3 μm reached 86.4%, while the pressure loss is just 32.5 Pa under the designed flow rate, which showed much higher capture efficiency and more acceptable flow resistance than those existing filter components.