Numerical Study on Deposition Characteristics of Soot Particles in Impeller of a Multi-Blade Centrifugal Fan

To reveal the distribution ol soot particle deposition in a multi-blade ccntrilugal Ian and mitigate such deposition, numerical simulations arc conducted to investigate the trajectories and deposition characteristics of soot particles within a multi-blade centrifugal fan. The study utilizes the Fluent discrete phase model to describe particle motion, while employing the critical velocity model and the user-defined functions (UDF) to model the particle deposition on walls. In addition, the study examines the particle diameter on deposition distribution. Findings indicate that soot particles mainly deposit on the blade pressure surface, with notable accumulation near the trailing edge close to the outlet. When the complete machine is involved, the flow field within the fan becomes more turbulent due to unstable inflow conditions, thereby leading to escalating deposition levels. It is found that particles with larger diameters exhibit a higher tendency to deposit on blade surfaces owing to the dominant inertial forces. In light of deposition distributions and their causal factors, an optimization strategy is proposed to reduce the deposition on blade surfaces by cutting blades and consequently reducing the outlet installation angle. In terms of the modified blades, flow separation near the impeller outlet decreases, leading to decreased vorticity around the trailing edge of blades. Comparing the original and modified blades, numerical simulation results show a 30. 75% decrease in deposition rate, while experimental outcomes demonstrate a 30. 66% reduction. The close agreement underscores the effectiveness of the proposed method in mitigating the deposition of soot particles. © 2024 Xi'an Jiaotong University. All rights reserved.