Fan blade
AssigneeROLLS-ROYCE plc
InventorMark J. Wilson
Life of this patent
Estimating the term…
Abstract
The suction surface blade angle of a transonic fan blade, subject in use to a shock wave, progressively reduces along part of the suction surface, beginning at a position upstream of the shock wave position. The increased area variation at the location of the shock results in the shock position becoming less sensitive to small geometric imperfections. The reduced shock sensitivity reduces the variation in aerodynamic load and hence reduces the untwist variation with respect to small geometric imperfections. This has the effect of stabilising the untwist deflections of the fan.
Claims11
A fan blade arrangement for a gas turbine engine, the arrangement comprising:
- a first blade having a leading edge, a trailing edge and a suction surface extending between the leading edge and the trailing edge;
- a second blade adjacent and generally parallel to the first blade;
- a covered passage defined by the first blade and the second blade, wherein
- the blade arrangement is subject to an air flow generally parallel to the suction surface and in a direction generally from the leading edge towards the trailing edge, the air flow giving rise to a shock wave associated with the leading edge of the second fan blade, the shock wave impinging on the suction surface of the first blade at a shock wave position, and
- a suction surface blade angle of the first blade progressively reduces in a direction generally from the leading edge towards the trailing edge along part of the suction surface so that the cross-sectional area of the covered passage between the first and second fan blades increases over an entire length of the covered passage such that the shock wave can move smoothly into and out of the covered passage.
Dependencies are inferred from the claim text.