System for determining the angular setting of an annular row of stator vanes

Patent metadata

Field	Value
Publication number	US-12221223-B2
Application number	US-202117995520-A
Country	US
Kind code	B2
Filing date	Apr 9, 2021
Priority date	Apr 10, 2020
Publication date	Feb 11, 2025
Grant date	Feb 11, 2025

Abstract

A method determines the angular setting (β_2) of an annular row of stator vanes arranged downstream of a pusher propeller of a propulsion system with a longitudinal axis. The annular row of stator vanes receives an air flow having a velocity (V2) including a longitudinal component (Viz) and a tangential component (V_iθ) associated with the velocity of gyration generated by the pusher propeller. The method includes the steps of establishing a theoretical model of the pusher propeller using a power (P1) and a mechanical speed (N1) associated with said pusher propeller, and flight conditions that include a velocity of the airflow incident on the pusher propeller, the altitude of said propulsion system and ambient temperature. The method further includes the step of determining an angular setting (β_1) of the pusher propeller from the theoretical model.

First claim

The invention claimed is:

1. A method for determining an angular setting (β 2 ) of an annular row of stator vanes arranged downstream of a pusher propeller of a propulsion system with a longitudinal axis, said annular row of stator vanes receiving an airflow having a velocity (V 2 ) including a longitudinal component (V iz ) and a tangential component (V iθ ) associated with a velocity of gyration generated by the pusher propeller, the method comprising the steps of:
a) establishing a theoretical model of the pusher propeller using a power (P 1 ) and a mechanical speed (N 1 ) associated with said pusher propeller, and flight conditions comprising a velocity of the airflow incident on the pusher propeller, an altitude of said propulsion system and ambient temperature;
b) determining an angular setting (β 1 ) of said pusher propeller from said theoretical model;
c) from said theoretical model of the pusher propeller, defining dimensionless parameters including at least a power coefficient (C p,1 ), a pull coefficient (C T,1 ) and an advance ration (J 1 ) of said pusher propeller defined by the following formulae:

C

P
,
1

=

P
1

ρ
·

N
1
3

·

D
1
5

C

T
,
1

=

T
1

ρ
·

N
1
2

·

D
1
4

J
1

=

V
0

N
1

·

D
1

wherein:
ρ corresponds to the density of an ambient air,
V 0 corresponds to a flight velocity of said propulsion system,
N 1 corresponds to said mechanical speed of said pusher propeller,
D 1 corresponds to a diameter of said pusher propeller,
P 1 corresponds to said power of said pusher propeller, and
T 1 corresponds to a pull of said pusher propeller;

d) calculating the longitudinal component (V iz ) and the tangential component (V iθ ) of said velocity (V 2 ) of the airflow incident on said annular row of stator vanes from said dimensionless parameters and deducing an angle (φ 12 ) between said velocity of the airflow incident on said annular row of stator vanes and a plane of rotation of said pusher propeller; and
e) determining an angular setting (β 2 ) to be applied to said annular row of stator vanes from said angle (φ 12 ), a Mach number associated with the velocity of the airflow incident on the pusher propeller and a database associating with each said angle (φ 12 ), different angular settings (β 2 ) of said annular row of stator vanes obtained for different Mach numbers,
wherein said angular setting (β 2 ) of said annular row of stator vanes is implemented by a FADEC system and communicated by the FADEC system to actuators which control the angular setting (β 2 ) of said annular row of stator vanes,

the method further comprising the step of controlling the angular setting (β 2 ) of said annular row of stator vanes by the FADEC system.

2. The method according to claim 1 , wherein said longitudinal component (V iz ) of said velocity (V 2 ) of the airflow incident on the annular row of stator vanes is calculated from the following formula:

V

i
⁢
z

=

V
0

2
⁢

J
1

[

J
1
2

+

K
1

·

C

T
,
1

-

J
1

]

wherein K 1 is a constant related to a radial dimension of the pusher propeller.

3. The method according to claim 1 , wherein said tangential component (V iθ ) of said velocity (V 2 ) of the airflow incident on the annular row of stator vanes is calculated from the following formula:

V

i
⁢
θ

=

K
2

·

V
0

·

C

P
,
1

Assignees

• Safran

Inventors

• Giannakakis Panagiotis
• Riera William Henri Joseph

Classifications

• B64F5/60

  Testing or inspecting aircraft components or systems · CPC title

• B64C11/30

  Blade pitch-changing mechanisms · CPC title

• B64D45/00 Primary

  Aircraft indicators or protectors not otherwise provided for · CPC title

• B64C11/00 Primary

  Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft · CPC title