Fans

Abstract

Fans are machines to move air or a similar gas. With regard to types, there are axial, radial and mixed-flow fans. Principles for the analysis of axial turbomachines have been elaborated in the foregoing chapters, but for radial machines, only a limited theory has been developed. The fan chapter is therefore also used to complete the theory for power receiving radial machines. It is appropriate to do this with the fan. Firstly, the fan is a simple turbomachine. Further, there are various rotor shapes with radial fans (forward curved blades, radial end blades and backward curved blades), as opposed to radial pumps (only backward curved blades) and radial compressors (radial end and backward curved blades). In this chapter, we also discuss the performance evaluation of radial fans, rotor design choices with radial fans and performance of axial and mixed-flow fans.