Investigation on Unstable Pressure Distribution of an Axial Fan Blade with Difference of Setting Angle and Chord Length

Abstract

Numerical analysis was carried out to investigate the influence of the setting angle and chord length on the pressure distribution especially for the shroud span of an axial fan. The setting angle was referred to as AOA (angle of attack). The aerodynamic performance of an axial fan with the change of setting angle and chord length was presented, and the unstable pressure distribution was discussed in detail. The airfoil of an axial fan was based on the NACA 3512. The influence of the setting angle was observed with the designed sets which were rotated based on the center of gravity for the blade. The chord length was adjusted while maintaining the setting angle. For each design parameter, 5 sets were designed to conduct the single-factor analysis, respectively. The setting angle had a sensitive effect on the aerodynamic performance of an axial fan. The pressure distribution became unstable related to the setting angle of the shroud span. On the other hand, the chord length was only proportional to the pressure rise and had a little effect on efficiency.