To address the contradiction between the low air pressure performance of air conditioner fans and the requirement for both high airflow and low noise, this study selected a high-performance axial flow fan prototype for air conditioning as a comparative research model for swept-back design. The prototype's basic structure includes: impeller outer diameter 409 mm, impeller hub diameter 120 mm, impeller hub ratio 0.29, 4 blades, flow rate 2220 m³/h, static pressure 20 Pa, and rotational speed 880 r/min. The new fan design prioritizes ensuring sufficient flow rate while focusing on improving the internal airflow distribution to reduce noise.
The design of the new fan is based on previous fluid dynamics research and existing quasi-three-dimensional design methods. It employs leading-edge sweep technology and a CFD/CAD coupling approach. The structural characteristics of a typical prototype impeller are estimated using CAD, and full three-dimensional CFD calculations are performed using the commercial software FLUENT to examine its external and internal flow characteristics. These results are then compared and analyzed with experimental results. A preliminary quasi-three-dimensional impeller design is performed using conventional methods, and CFD calculations are conducted to examine its external and internal flow characteristics. The CAD/CFD results of the prototype fan and the new fan are compared and analyzed, and relevant parameters in the initial design are adjusted to achieve a better aerodynamic layout. CFD is used to predict the performance of the adjusted fan, and relevant parameters are further adjusted based on the calculation results to further optimize the fan.
In addition, parameters such as blade chord length, blade installation angle, airfoil camber angle, and airfoil mid-curvature are also considered in the design. Optimized values and reasonable matching of these parameters are performed to improve the fan's aerodynamic and acoustic performance.
