Optimum number of blades for maximum efficiency of centrifugal blowers

A BLOWER is a rotodynamic machine converting the mechanical energy into fluid energy. Its performance represents the combination of performance of all the components. In the present study the number of blades has been chosen as a variable, keeping the rest of the system same. Earlier work done by Kearton showed that 16 bladed impeller out of the 4 impellers studied by him gave good overall performance. Theoretical considerations of Stodola, Busemann and Pfleiderer indicated that the blade exit angle and the number of blades controlled the unit's performance. Recently Bommes carried out extensive experiments on blowers by varying both the blade exit angle and the number of blades. When Pfleiderer's method was used to predict the number of blades, the predictions were not in agreement with the experiments. In this a theoretical equation has been developed which agrees well with the experimental results.