Investigating the effect of axial fan shrinkage obtained by centrifugal casting technology on aerodynamic characteristics

Abstract

Centrifugal casting technology was developed for the application of manufacturing axial fans. In the literature, these fans were usually manufactured by injection molding, mechanical processing or heat pressing. The main characteristic of this molding technology allows the creation of thick and hollow blades. This characteristic of the blades gives useful advantages of the fan that cannot be achieved by conventional methods. The centrifugal casting technology has been applied to fabricate axial fans in recent research. However, the issue of quality control and especially the shrinkage of the resulting fan compared to the molding has not yet been considered. Therefore, more in-depth studies and approaches are required. In this study, 3D scanning method is used to evaluate the shrinkage of the blades. The used 3D scanner is the Comet L3D 5M type based on structured light (blue LED) with a 5-megapixel sensor. This device achieves high accuracy and reliability (resolution 18 μm). The theoretical basis for determining fan shrinkage compared to CAD molds is based on the following main parameters: Chord line L (mm), relative thickness Emax (%), and stagger angle ( (degrees). In addition, the aerodynamic characteristics of the proposed fan are compared to those of a fan made of aluminum (blades are identical, but different in fabricating technology). Characteristics of this aluminum rigid-fan are assumed as reference. The results showed that the difference was not large between the blades. Besides, the results of aerodynamic testing on the test bench of the two fans are almost similar. This indicates the good adaptability of the axial fan received by the centrifugal casting technology.