New Type Axial Flow Fan Rotors Design And Aerodynamic Acoustics Performance Study

Current industrial axial flow fan has disadvantage of low efficiency high noise and so on, select of axial flow fan blade airfoil properly combined with swept can improve aerodynamic efficiency,reduce aerodynamic noise and extend stable operating range, but the research is largely concentrated in low speed airfoil with skewed swept characteristics, research on high speed airfoil junction and swept curved features is relatively less.Isolated airfoil design method and variable circulation flow pattern combined with three dimensional modeling is used in design circumferential skewed NACA65 airfoil section blade, simulate and analysis the Rotors' aerodynamic and aero-acoustic performance with CFD method. The results showed that :(1)The blade stacking line circumferential bending has no consistent influence on the aerodynamic and aero-acoustic performance, circumferential bending originally increase then decrease efficiency and pressure rise when operating under design flow rate, forward bending increase both characteristics while backward decrease working above certain design flow rate;(2)The blade loading characteristic is changed by the circumferential bending, forward bending increase the blades performance ability as well as flux ability, while backward bending decrease;(3)The radial pressure gradient is changed for occupying circumferential bending, blade forward bending increases this gradient, thus is helpful to limit low energy flux resulted from the flow separation to transport to the tip wall, but is aided to the energy loss along the transportation road; while reverse bending reduces this gradient, thus has the reverse influence on the energy loss;(4)Tip leakage flow structure is changed, the origin of the vortex is delayed and its dissipation extent is increased when employing the forward bending, the radial height of the vortex core is kept; while the occurrence of the vortex is advanced and the dissipation extent is decreased, the radial height is largely lowed when using reverse bending;(5)The tip leakage vortex sound development path consistent with the vortex core, forward bending delays the formation of the sound and decreases its strength and stability, speed up the vortex sound disappear, while the reverse bending bring forward the formation of the vortex sound, the strength and stability is increased as well, thus slow down the disappear of the sound.NACA airfoil combined with curved stacking line is used in design axial flow fan, the related results of numerical simulation and experimental verification enrich the research inhigh speed airfoil applied in the low pressure axial flow fan and provide a reference.