The internal relation between a large number of existing aerodynamic sketches and performance parameters of centrifugal fan is analyzed and investigated by means of statistical method

the correspondence relation between speed coefficient and diametral quotient

impeller outlet breadth and diametral quotient is found.A new method which determined the main geometric parameters of impeller is put forward.On the base of the software of CAD

the CAD module of impeller of centrifugal fan with VBA using the parametric drawing technology is developed

and the automatation of design and drawing of impeller is realized

efficierry and the quality of drawing are improved.