CFD method could replace experiment for development of a fan, but it cannot be applicable to some of real design stage because of limitation that rotating speed must be set as boundary condition. That is, most experiments without a Dynamo set only voltage of a motor as input condition. The remarkable difference between the above mentioned experiment and the current CFD is that the rotating speed varies with flow rate. Therefore, the numerical results calculated by the boundary condition of constant rotating speed have limitation of real application, and especially, when predicting efficiency, there exists a striking difference from the real situation. In this article, we developed a new algorithm in which we are able to determine both static pressure and rotating speed through setting up the only voltage as a boundary condition with motor performance test results. The new developed algorithm on the basis of experiment and CFD showed good qualitative and accurate results with a significant difference of less than 5%. (C) 2011 Elsevier Ltd. All rights reserved.