Outlet guide vane

Abstract

An outlet guide vane for an axial compressor extending along a rotor axis, includes an airfoil extending in a span direction from a radially inner end at 0% height to a radially outer end at 0% height. The airfoil has a suction side and an opposite pressure side, both sides extending in a chord direction from a leading edge to a trailing edge, wherein for each profile of the airfoil a stagger angle between the chord and the rotor axis is defined. A more favorable air flow profile behind the outlet guide vane is achieved by a new shape of the outlet guide vane, wherein a stagger angle distribution in the span direction has a curved course having a minimum located between 40% and 60% in the span direction, a first maximum at 0% and a second maximum at 100% in the span direction.

Claims

1. An outlet guide vane for an axial compressor extending along a rotor axis, comprising: an airfoil extending in a span direction from a radially inner end at 0% height to a radially outer end at 100% height, the airfoil comprising a suction side and an opposite pressure side, the suction side and the opposite pressure side extending in a chord direction from a leading edge to a trailing edge, wherein for each profile of the airfoil a stagger angle between the chord and the rotor axis is defined, wherein a distribution of the stagger angles in the span direction comprises a curved course comprising a minimum located between 40% and 60% in the span direction, a first maximum at 0% height and a second maximum at 100% height in the span direction, wherein the stagger angle at the minimum is between 1° and 7°.

2. The outlet guide vane according to claim 1, wherein the difference in the stagger angle between the minimum and the first maximum is between 8° and 23°.

3. The outlet guide vane according to claim 1, wherein the difference in the stagger angle between the minimum and the second maximum is between 6° and 22°.

4. The outlet guide vane according to claim 1, wherein each chord comprises a chord length, and wherein a longest chord length of the chord lengths is at the radially outer end.

5. The outlet guide vane according to claim 1, wherein the stagger angle at the first maximum is between 14° and 26°.

6. The outlet guide vane according claim 1, wherein the stagger angle at the second maximum is between 8° and 28°.

7. An axial compressor, comprising: a plurality of outlet guide vanes according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention are now described, by way of example only, with reference to the accompanying drawings, of which:

(2) FIG. 1 shows in a perspective view a pressure side an outlet guide vane according to the present invention,

(3) FIG. 2 shows in different perspective view the pressure side the outlet guide vane according to FIG. 1,

(4) FIG. 3 shows a profile of an outlet guide vane, and

(5) FIG. 4 shows the stagger angle distribution in the span direction for the outlet guide vane shown in FIG. 1.

(6) FIG. 5 schematically represents an axial compressor having a plurality of outlet guide vanes according to FIG. 1.

DETAILED DESCRIPTION OF INVENTION

(7) It is noted that in different figures, similar or identical elements are provided with the same reference signs.

(8) FIG. 1 and FIG. 2 show an outlet guide vane 2 for an axial compressor which is not shown in detail. The axial compressor is e.g. an industrial gas compressor or is part of a gas turbine engine and is operated under subsonic conditions. The axial compressor comprises at its rear end a ring having a plurality of such outlet guide vanes 2. The axial compressor extends in the direction of rotor axis, which in FIG. 1 is parallel to the x-axis.

(9) The outlet guide vane 2 comprises an airfoil 4 having an upstream-sided leading edge 6 and a downstream-sided trailing edge 8 between which a suction side (not shown) and a pressure side 10 extend in chord direction. The radial height of the airfoil 4 is determined from its radially inner end 12 with 0% height to its radially outer end 14 with 100% height. The span direction of the airfoil 4, which is also equivalent to the radial direction of the compressor, is in FIG. 1 parallel to the z-axis.

(10) For each height position of the airfoil 4, following the fluid streamlines, a profile can be determined. One such exemplary profile 16 is shown in FIG. 3. The profile 16 represents the outer airfoil shape for a specific height of the airfoil 4 defined by a cross section, in particular parallel to the x-y plane through said airfoil 4 at said height rotor axis. For each profile a stagger angle γ is determinable between a chord line C of the profile and the rotor axis x. Hereby the chord line C is an imaginary straight line joining the leading edge 6 and trailing edge 8 of the airfoil 4.

(11) As can be seen in FIG. 1 and FIG. 2, the longest chord length for the airfoil 4 is at the radially outer end 14.

(12) FIG. 4 shows the distribution of the stagger angle γ in the span direction z from the radially inner end 12 at 0% height to the radially outer end 14 at 100% height. The distribution line D has a curved, u-shaped course having its minimum A located between 40% and 60% in the span direction z. A first maximum M.sub.1 of the u-shaped line D is at the radially inner end 12, i.e. at 0% height, and a second maximum M.sub.2 is at the radially outer end 14, i.e. at 100% height.

(13) In FIG. 4 the stagger angle γ in the minimum A is approximately 3°. In general, the stagger angle γ at this point is between 1 and 7. The stagger angle γ at the first maximum M.sub.1 (at the radially inner end 12, 0% in span direction) is approximately 24° and the stagger angle γ at the second maximum M.sub.2 (at the radially outer end 14, 100% in span direction) is approximately 16°. Hence, the difference in the stagger angle γ between the minimum A and the maximum at the radially inner end is 21° and the difference in the stagger angle γ between the minimum A and the maximum at the radially outer end is 13°. In the embodiment shown in FIG. 4 also the stagger angle γ in the second maximum M.sub.2 is smaller than the stagger angle γ in the first maximum M.sub.1.

(14) FIG. 5 schematically represents an axial compressor 20 having a plurality of outlet guide vanes 22 according to FIG. 1.