Development of improved design and 3D printing manufacture of cross-flow fan rotor

Abstract

This study determined the optimum blade stagger angle for a cross-flow fan rotor and evaluated the performance of a 3D printed rotor. Using ANSYS-CFX and SolidWorks, the cross-flow fan was modeled computationally and tested at 8,000 rpm. A parametric study determined optimum blade stagger angle using thrust, power, and thrust-to-power ratio as desired output variables. A MarkForged Mark One 3D printer was used to print components of a carbon-fiber composite cross-flow fan rotor. These pieces were assembled and the thrust, power, and thrust-to-power ratio of the 3D printed rotor were measured. These performance characteristics were compared to a rotor of the same geometry previously manufactured from traditional carbon fiber components. The optimum stagger angle for the current 26-bladed, 101.6 mm (4 inch) diameter rotor was determined to be 10¡ forward of its previous position. The 3D printed rotor was found to produce less thrust, but also required less power. This was thought to be caused by the outward deflection of the rotor blades due to centripetal force in conjunction with the surface roughness of the blades. The rotor did have a similar thrust-to-power ratio as the current cross-flow fan rotor at speeds of up to 8,000 rpm.