Turbomachine with serrated-profile flow-splitter nose

Patent metadata

Field	Value
Publication number	US-11525365-B2
Application number	US-201916970526-A
Country	US
Kind code	B2
Filing date	Feb 15, 2019
Priority date	Feb 16, 2018
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

A front fan turbomachine includes an annular separating wall having a slat for separating an air flow between a primary flow and a secondary flow, the slat having a leading edge; inlet guide vanes (IGV) for guiding the primary flow and outlet guide vanes (OGV) blades for guiding the secondary flow. The leading edge of the slat has a serrated profile having a succession of teeth and depressions.

First claim

The invention claimed is:

1. A turbomachine having a front fan ( 14 ) in which an airflow can circulate from upstream to downstream, the turbomachine having a general axis (X) about which the front fan can rotate, the front fan generating a wake downstream when it rotates, the turbomachine comprising:
an annular dividing wall ( 160 ) having a slat ( 16 ), for dividing the airflow downstream of the fan ( 14 ) into a primary flow and a secondary flow, the slat ( 16 ) having a leading edge,
first guide vanes (IGV 24 ) for guiding the primary flow (Fp),
second guide vanes (OGV 26 ) for guiding the secondary flow (Fs),

characterised in that the leading edge of the slat ( 16 ) of the annular dividing wall ( 160 ) has a serrated profile ( 28 ) having a succession of undulations comprising teeth ( 30 ) and depressions ( 32 ):
that define:
along a direction (L) of elongation of the leading edge, a repeating elementary geometry, two identical undulations of two successive elementary geometries ( 34 , 36 ) along said direction (L) having between them, along said direction, a distance (λ),
and a maximum amplitude (h), perpendicular to said direction (L) along which the leading edge has a length, and

which meet at least one of the following criteria a), b), c):

a) the maximum amplitude (h) is dimensioned according to the relation: l 11 (1) /h<1 to within 40%, using the equation:

l
ij

(
k
)

=

∫
0
∞

⁢

〈

u
i
′

⁡

(

x
+

rn
k

)

⁢

u
j
′

⁡

(
x
)

〉

〈

u
i
′

⁡

(
x
)

⁢

u
j
′

⁡

(
x
)

〉

⁢
dr

to calculate the integral length scale of the i-th and j-th fluctuating velocity components in the k-th spatial direction, where:
i, j and k are subscripts that define spatial directions;
x corresponds to a position of a point in the flow field;
u′ i corresponds to the airflow ( 38 ) turbulent velocity component in i-th direction, between the front fan ( 14 ) and the first guide vanes ( 24 , IGV);
u′ j corresponds to the airflow ( 38 ) turbulent velocity component in the j-th direction;
r corresponds to the distance between two points downstream of the front fan ( 14 ) in the k-th direction;
n k is a unit vector in the k-th direction; and
l 11 (1) corresponds to the integral length scale of the airflow ( 38 ) generated by the front fan ( 14 ), in the direction of a chord ( 40 ) of the profile, or parallel to the general axis (X) of the turbomachine,

b) said distance (λ) respects the following relationship:
e<λ≤d−e where d/λ≠ 1, 2, 3, . . . , where
e corresponds to the width of the airflow ( 38 ) generated by a blade ( 140 ) from the front fan ( 14 ), said width being calculated at a point where half of the maximum turbulent kinetic energy, K_max, generated in said wake is found; e being estimated from the criterion e =l 22 (2) /0.21 to within 40% where l 22 (2) corresponds to the integral length scale of the airflow ( 38 ) generated by the front fan ( 14 ), in the circumferential direction ( 40 ) of the profile, or perpendicular to the general axis (X) of the turbomachine; and
d corresponds to the spacing between two circumferentially consecutive blades ( 140 ) of the front fan ( 14 ),

c) the number of teeth ( 30 ), depressions ( 32 ), or repetition periods of the elemental geometry along the length of the leading edge is equal, within 40%, to the number of the first guide vanes ( 24 , IGV).

2. The turbomachine according to claim 1 , wherein:
the first guide vanes ( 24 , IGV) have an angular position (β) with respect to the general axis (X), and
around said general axis (X), at least some of said depressions ( 32 ) of the serrated profile ( 28 ) are angularly offset with respect to the angular position (β) of the first guide vanes ( 24 , IGV), so that said at least some of the depressions ( 32 ) are angularly interposed between two consecutive first guide vanes ( 24 , IGV) in the circumferential direction.

3. The turbomachine according to claim 2 , wherein:
the front fan ( 14 ) is adapted to rotate in a predetermined direction (Y) about said general axis (X) such that the airflow ( 38 ) downstream of the fan is obliquely oriented with respect to said general axis (X) at an angle (α), and
the teeth ( 30 ) are inclined circumferentially around said general axis (X) towards the oblique orientation (α) of the airflow downstream of the front fan ( 14 ).

4. The turbomachine according to claim 2 , wherein:
the first guide vanes ( 24 , IGV) individually have a camber line ( 240 ) and a leading edge ( 25 ), and
the teeth ( 30 ) are, circumferentially around said general axis (X) and individually, oriented generally in the direction of a tangent ( 42 ) to the camber line ( 240 ) of a respective guide vane of said first guide vanes ( 24 , IGV) passing by the leading edge ( 25 ) of the respective guide vane, said tangent forming a (β) non-zero angle with respect to the direction of the general axis (X) of the turbomachine.

5. The turbomachine according to claim 2 , wherein:
the depressions ( 32 ) of the serrated profile ( 28 ) have bottoms ( 320 ), and
in the direction of said general axis (X), at least some of said bottoms ( 320 ) of the depressions belong to a first surface (Y 1 , Y 2 ) which is transverse to said general axis (X) and is positione

Assignees

• Safran Aircraft Engines

Inventors

• Gea Aguilera Fernando
• Fiack Matthieu
• Gruber Mathieu Simon Paul

Classifications

• F15D1/0035

  in the form of riblets · CPC title

• F05D2220/323

  for aircraft propulsion, e.g. jet engines · CPC title

• F02C7/045

  having provisions for noise suppression · CPC title

• F02K1/386

  mixing devices in the jet pipe, e.g. for mixing primary and secondary flow · CPC title

• F15D1/004

  oriented essentially parallel to the direction of flow · CPC title