Effects of external disturbances on the performance of an axial cooling fan

In this study flow around an axial flow fan is investigated by the means of CFD computations using the commercial software package, ANSYS Fluent. The rotation speed of the impeller was set to the constant value of n = 2500min-1. The results obtained from the computation are validated against those from measurements; good agreements can be seen. The effects of two different external disturbances are analysed. First, the fan was place into a uniform stream where the free stream velocity is varied between U = 0 and 100 km/h. After that, a computation is carried out for U = 0 km/h where the half of the suction side of the fan was covered by a flat plate. The results showed that the fluid pressure and the aerodynamic force increases with the free stream velocity. Asymmetric pressure and fluid force distribution was identified when suction side of the fan was partially covered.