| 摘要 |
An aerofoil is rotatable through a large range of pitch angles relative to a hub body. The hub has a diameter that is comparable to, or smaller than, the aerofoil chord to expose the aerofoil inner edge to rotational flow local to that body at large pitch angles relative to the body centre-line. At this condition, up to three leading edges are seen, each with typical and similar or dissimilar aerofoil cross-sections along lines where the fluid flows. At small angles relative to the body the aerofoil seats against the body surface. At this condition one train leading edge is seen with a typical and similar or dissimilar aerofoil cross-section to the first condition along lines where the fluid flows. These allow differing aerofoil sections to be exposed at different pitching angles and rotation rates to enable a rotor to be used over a large range of operating conditions. |
