Optimization of Impeller to Reduce Deposition of Soot and Oil Particles Within a Multiblade Centrifugal Fan

Abstract In this work, a discrete phase model (DPM) is applied to simulate the transport of soot and oil particles in a multiblade centrifugal fan, in which a critical velocity model is established to model the particle deposition, rebound, and detachment on the blade surface. Alongside the DPM simulations, a multi-objective optimization of the blade profile is conducted with the objective of improving the aerodynamic performance of the fan and reducing the deposition of soot and oil particles on the impeller, which employs a self-adaptive updated Kriging model, the Latin hypercube sampling method and the non-dominated sorting genetic algorithm II to find tradeoff solutions. The results indicate that the aerodynamic performance of the fan is most influenced by the outlet angle, and increasing outlet angle is beneficial to increasing the total pressure and flowrate. The deposition of particles on the impeller is greatly affected by the outlet angle and wrap angle, and increasing outlet angle and decreasing wrap angle both lead to a significant reduction of the particle deposition on the impeller. For either baseline or optimized blade, the regions with high entropy generation rate are mainly distributed near the leading and trailing edges, while the entropy generation rate is greatly reduced after optimization. For the optimized blade, the deposition distribution is similar to the baseline blade, but the deposition rate is decreased by 40.5%, which agrees well with the experimental results.