Effects of bowed and swept blade on the improvement of transonic fan performance and inhibition of the flow loss were studied by numerical simulation based on a small transonic axial fan.The swept and bowed design concept for the up half spanwise of rotor and later half spanwise of stator was discussed at the design flow condition and the less flow condition.The results show that negative bowed design for up half spanwise of rotor changes the pressure gradient near the endwall

thus

the accumulation of boundary layer near the side of pressure surface at outlet caused by the leakage flow is decreased

and the flow capacity is enhanced.The negative bowed design at leading edge and positive bowed design at trailing edge were adopted in the design of stator.The complex bowed and twisted technology can realize the increase of flow rate near the endwall and the control of the secondary flow at the same time.The bowed and twisted stator can also control the deterioration of secondary flow better with the decrease of flow rate and enlarge the range of steady operation condition obviously.