A design philosophy for centrifugal fans

This thesis outlines the areas that need to be considered during the design and development of centrifugal fans, and in particular noise reduction techniques. The main subjects covered are: (a) fan performance and noise level assessment; (b) a description of the various fan types available and their uses; (c) an explanation of how specific speed and performance coefficients can be used to determine the optimum fan type for a given application; (d) fan design concepts and their effect on noise and performance; (e) performance and noise level prediction methods; (f) experimental methods used for the design and selection of fans; (g) vibration measurement and balancing techniques; (h) stress calculations and tests to confirm the mechanical integrity of fans. During this research a new range of fans for use in industrial dust collectors has been developed which offer the following improvements over the existing fan range: (1) increased efficiency and associated power savings; (2) reduced noise levels; (3) cost savings.