Effects of non-smooth blade on the aerodynamic performance of an axial fan

An experimental investigation of effects of two kinds of streamwise-grooved blades on the performance of an axial-flow fan was performed on an axial fan test rig. The flow field at 25% chord downstream from the trailing edge at hub was measured using a mini 5-hole pressure probe at different mass-flow conditions. The fan performance of the grooved blades was compared with that of the smooth blades. The measurement results indicate that: (1) the grooved blade-surfaces increase the fan's mass flow, reduce the relative total pressure loss and increase the fan's total pressure rise at the test mass-flow conditions except the near stall condition; (2) Negative benefits were obtained at the near stall condition when the smooth blades are replaced by the non-smooth ones; (3) Effects of non-smooth blades depend on the groove geometry to a certain extent.