For a single-stage variable-pitch axial fan, the aerodynamic performance and through flow with and without blade skewing are examined numerically. Simulated results show that the total pressure rise and efficiency increase by 2.99% and 0.16%, respectively, with the best forward-skewed angle of θ = 3° at the design conditions. At the blade pitch angles of β = 29° and 35°, the total pressure rises and efficiency of the fan with θ = 3.0° under the highest efficiency point change by −0.55%, −0.53% and 1.39%, 2.11%, respectively. At design and off-design conditions, the forward-skewed blades mitigate tip leakage and delay the emergence of separation flow at the blade root, these benefits are higher at the higher blade pitch angle. The θ = 3.0° forward skew effectively raises the stage performance of the impeller and guide vanes.

No abstract

：The chordwise swept blades is an effective way to improve the aerodynamic performance of large axial fans. For a single-stage variable-pitch axial fan of type OB-84 with rear guide vanes, the aerodynamic performance and internal dynamics of the fan before and after blade sweeping are simulated with Ansys software, the static structure features are investigated, and the noise is predicted, as well as the influence of the sweep angle at different blade angles is examined. Simulated results show that under the design blade angle, the forward-swept blade can effectively raise the working ability of impeller and pressure recovery ability of guide vanes, reduce the leakage loss, and then the fan performance is improved, especially in the small and large flow rate. The forward-swept angle of 8.3° has the best performance at the design point and the total pressure and efficiency are increased by 2.1% and 1.68%, but the noise is increased. After the blades swept, the aggravated deformation still meets the requirements of material strength. The performance of the forward swept blade fan is reduced under variable blade angle conditions, so the best forward-swept angle obtained at the design blade angle is suitable for fans operating at rated loads.