US 12,221,223 B2
System for determining the angular setting of an annular row of stator vanes
Panagiotis Giannakakis, Moissy-Cramayel (FR); and William Henri Joseph Riera, Moissy-Cramayel (FR)
Assigned to SAFRAN, Paris (FR)
Appl. No. 17/995,520
Filed by SAFRAN, Paris (FR)
PCT Filed Apr. 9, 2021, PCT No. PCT/FR2021/050636
§ 371(c)(1), (2) Date Oct. 5, 2022,
PCT Pub. No. WO2021/205133, PCT Pub. Date Oct. 14, 2021.
Claims priority of application No. 2003639 (FR), filed on Apr. 10, 2020.
Prior Publication US 2023/0150688 A1, May 18, 2023
Int. Cl. B64D 5/00 (2006.01); B64C 11/00 (2006.01); B64D 45/00 (2006.01); B64F 5/60 (2017.01)
CPC B64D 45/00 (2013.01) [B64F 5/60 (2017.01)] 5 Claims
OG exemplary drawing
 
1. A method for determining an angular setting (β2) 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 (V2) including a longitudinal component (Viz) and a tangential component (Viθ) 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 (P1) and a mechanical speed (N1) 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 (β1) 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 (Cp,1), a pull coefficient (CT,1) and an advance ration (J1) of said pusher propeller defined by the following formulae:

OG Complex Work Unit Math
wherein:
ρ corresponds to the density of an ambient air,
V0 corresponds to a flight velocity of said propulsion system,
N1 corresponds to said mechanical speed of said pusher propeller,
D1 corresponds to a diameter of said pusher propeller,
P1 corresponds to said power of said pusher propeller, and
T1 corresponds to a pull of said pusher propeller;
d) calculating the longitudinal component (Viz) and the tangential component (Viθ) of said velocity (V2) of the airflow incident on said annular row of stator vanes from said dimensionless parameters and deducing an angle (φ12) 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 (β2) to be applied to said annular row of stator vanes from said angle (φ12), a Mach number associated with the velocity of the airflow incident on the pusher propeller and a database associating with each said angle (φ12), different angular settings (β2) of said annular row of stator vanes obtained for different Mach numbers,
wherein said angular setting (β2) 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 (β2) of said annular row of stator vanes,
the method further comprising the step of controlling the angular setting (β2) of said annular row of stator vanes by the FADEC system.