Abstract: Fan blades shape affects its effective and sound pressure level (SPL). The fan blades noise types are analyzed. It studies fan blades airflow dynamic noise principle. It thinks about the blade structure shape in particular. The property of sound field produced by moving sound source is used. Mathematical model of fan blades noise is created. The mathematical model is calculated by advanced precision Gauss—Legendre. It studies the change of fan blades noise when the model parameters ( number of blades, rotation of fan, camber angle, spanwise radius of fan, section parameter of fan etc. ) are changed. The simulating and experiment results are analyzed. The factors of airflow dynamic noise are discussed. It can provide theory for low noise design and prediction of fans.

Key words: Airflow dynamic noise, Fan blade, Mathematical model calculate, Model parameters