| 摘要 |
An axial fan rotatably mounted in a cylindrical duct ring 3 has a plurality of fan blades 2 with peripheral blade tips 4 describing, in operation, a circular path adjacent the duct ring 3. The blade tips 4 each have a leading edge 6 in the axial direction, a trailing edge 9 and a tip outer surface, at least one of the edges 6,9 and/or the outer surface having a non-uniform profile for influencing the flow of air over the said tip outer surface. The non-uniform profile may take the form of undulations, grooves or steps. A flange 5 may be provided at the blade tip. |
