Performance Model Development for the Adjustable Blades Axial Flow Fan Based on Multivariate Polynomial Fitting

To obtain a performance model for the adjustable blades axial flow fan, the performance surface of fan was fitted using binary polynomial fitting method, and the coefficients matrix was solved with QR decomposition. By comparing the fitting results show that the fitting effect is good when the 5 order polynomial was used to fit the performance surface of the fan and the 6 order polynomial was used to fit the boundary of performance surface. The accuracy of the obtained model can meet the requirements of the engineering application and scientific research.