Abstract
In order to clarify the tip vortex features occurring in an open fan without an outer casing, the experimental investigation was carried out for two types of rotor blade. One has the radial straight leading edge similar to the ducted fan blade, and the other has the forward curved leading edge mainly used in a room ventilation fan blade. The flow fields around each rotor were measured using the two-components LDV system. The structure and behavior of the tip vortex for each rotor were clarified and the differences of the tip vortex nature were discussed. As a result, it is shown that the features of the tip vortex occurring in an open fan are affected by the blade shapes and the blade loading parameter.
