System for determining angular setting of annular stator vane rows

Abstract

The present document relates to a method for determining an angular setting (β2) of an annular stator blade row arranged downstream of a propulsive propeller of a propulsion system having a longitudinal axis, said annular stator blade row receiving an airflow having a velocity (V2) comprising a longitudinal component (V iz ) and a tangential component (V iθ ) associated with the velocity of the revolution generated by said propulsive propeller, said method comprising the steps of: establishing a theoretical model (14) of said propulsive propeller using a power (P1) and a mechanical speed (N1) associated with said propulsive propeller (4) and flight conditions (16) comprising the velocity of the airflow incident on said propulsive propeller, the height of said propulsion system and the ambient temperature; determining an angular setting (β1) of said propulsive propeller from said theoretical model (14).

Description

Technical Field

[0001] This document relates to determining the angle settings of the annular stator blade array downstream of the propeller in an aircraft's propulsion system. Background Technology

[0002] Normally, such as Figure 1 As described, the aircraft includes a propulsion system 1 with a longitudinal axis 2, the longitudinal axis comprising a propeller 4 formed by an annular row of blades movable around the longitudinal axis 2. An annular stator blade row 6 is arranged downstream of the propeller 4 to convert the rotation caused by the propeller 4 into axial propulsion velocity, thus increasing the generated thrust. Upstream and downstream are defined relative to the gas circulation direction within the propulsion system.

[0003] It is known that the blade angle settings of the propeller 4 are configured to optimize aircraft propulsion. However, although the stator blade 6 configuration is also known, no details are provided regarding the methods and calculations required to achieve the optimized angle settings of the annular stator blade array 6, which varies with the flight phase.

[0004] The implementation scheme for the control rules used for setting the angle is complex, and there is no optimized, simple, and effective system for setting the annular stator blade row 6 arranged at an angle downstream of the propeller 4 of the aircraft propulsion system, which may also be a variable-pitch propeller.

[0005] This document aims to address these shortcomings in a simple, reliable, and cost-effective manner. Summary of the Invention

[0006] This document relates to a method for determining the angular arrangement of an annular stator blade bank arranged downstream of a propeller in a propulsion system having a longitudinal axis, the annular stator blade bank receiving an airflow having a velocity V2, the velocity including a longitudinal component V. iz and the tangential component V associated with the rotational speed generated by the propeller. iθ The method includes the following steps:

[0007] a) Establish a theoretical model of the propeller using the power P1 and mechanical speed N1 associated with the propeller and flight conditions, including the speed of the airflow incident on the propeller, the altitude of the propulsion system, and the ambient temperature.

[0008] b) Determine the angle setting of the propeller based on the theoretical model;

[0009] c) Based on the theoretical model of the propeller, define a dimensionless parameter that includes at least the power coefficient C of the propeller as defined by the following formula. p,1Tensile coefficient C T,1 And approach ratio J1:

[0010]

[0011]

[0012]

[0013] in

[0014] ρ corresponds to the density of ambient air.

[0015] V0 corresponds to the flight speed of the propulsion system.

[0016] N1 corresponds to the mechanical speed of the propeller.

[0017] D1 corresponds to the diameter of the propeller.

[0018] P1 corresponds to the power of the propeller.

[0019] T1 corresponds to the thrust of the propeller;

[0020] d) Calculate the longitudinal component V of the velocity V2 of the airflow incident on the annular stator blade bank based on the dimensionless parameters. iz and tangential component V iθ Furthermore, the angle between the velocity of the airflow incident on the annular stator blade array and the plane of rotation of the propeller is derived.

[0021] e) Determine the angle settings to be applied to the annular stator blade row based on the angle, the Mach number associated with the velocity of the airflow incident on the propeller, and a database associated with each angle, and obtain different angle settings for the annular stator blade row for different Mach numbers.

[0022] A database is pre-constructed to facilitate real-time angle setting as the propeller position changes. In practice, the propeller angle setting is obtained based on the power and mechanical speed associated with the propeller, the velocity of the airflow incident on the propeller, the altitude of the propulsion system, and the ambient temperature. The method can then determine the optimal angle setting for each of the stator blades based on the database.

[0023] The method of determining the angle setting to be applied to the annular stator blade array provided herein makes the control of the annular stator blade array easier to implement and more stable to changes in flight conditions, such as the velocity of the airflow incident on the propeller, the altitude of the propulsion system, and the ambient temperature. Here, ambient temperature refers to the temperature of the surrounding environment in which the propulsion system is located.

[0024] The optimal thrust of the propulsion system can be obtained by using the optimal angle setting of the annular stator blade row, which varies with the configuration of the propeller.

[0025] The axial component V of the velocity V2 of the airflow incident on the annular stator blade array can be calculated using the following formula. iz :

[0026]

[0027] Where K1 is a constant related to the radial dimension of the propeller.

[0028] The tangential component V of the velocity V2 of the airflow incident on the annular stator blade array can be calculated using the following formula. iθ :

[0029]

[0030] K1 and K2 are constants related to the radial dimension of the propeller.

[0031] The angle The following formula can be followed:

[0032] The angle setting β2 of the annular stator blade row can be transmitted to the actuator through the FADEC system, and the actuator controls the angle setting β2 of the annular stator blade row.

[0033] In terms of its operation, this method requires less data and is therefore easier to implement in calculators such as FADEC (Full Authority Digital Engine Control).

[0034] The database can be a table constructed through simulation or testing, in which multiple operating conditions are calculated based on all combinations of parameters such as rotor speed N1, flight Mach number, propeller angle setting β1, and annular stator blade row angle setting β2, thereby deriving the results as the flight Mach number and angle change... The maximum tension coefficient C′ varies with the angle β2 of the annular stator blade row. T,2 The table.

[0035] The advantage of this database is that it allows for very fast information access. In fact, once the database is created, it is simply a matter of reading the optimal value of the angle setting β2 for the annular stator blade row. The database is also less complex, thus allowing for integration into FADEC. Attached Figure Description

[0036] [ Figure 1 [Illustration] is a schematic diagram of a propeller system with an annular stator blade array.

[0037] [ Figure 2 [Illustration] is a schematic diagram of airflow, and more precisely, a schematic diagram of the velocity of that flow received by a propeller.

[0038] [ Figure 3 [This is a schematic diagram of airflow, and more precisely, it is caused by...] Figure 3 The diagram shows the velocity of the flow received by the annular stator blade array downstream of the propeller.

[0039] [ Figure 4 [Illustration] is a schematic diagram illustrating a method for determining the angle setting of a propeller and the angle setting of an annular stator blade array downstream of the propeller.

[0040] [ Figure 5 [This is a schematic diagram of the operation of the setting model of the annular stator blade row.] Detailed Implementation

[0041] Figure 2 Explanation based on Figure 1 The airflow at the inlet of the rotating propeller 4 of the propulsion system 1, which has a longitudinal axis 2. When the propeller 4 has an angle setting β1, it then receives air at a flight speed V0 oriented perpendicular to the longitudinal axis 2.

[0042] In this configuration, such as Figure 3 As shown, the annular stator blade row 6, located downstream of the propeller 4, subsequently receives an airflow with a velocity V2, the velocity comprising the flight velocity V0 (longitudinal only) and a longitudinal velocity V. iz The longitudinal component and the tangential component V iθ V iz This represents the longitudinal component and the tangential component V associated with the rotational speed generated by the propeller 6. iθ .

[0043] The angle between the velocity of the airflow incident on the annular stator blade row 6 and the plane of rotation 8 of the propeller 4 The aerodynamic performance of the annular stator blade row 6 is crucial for defining this. This is combined with the angle setting β2 applied to the annular stator blade row 6. Define the angle of attack. If the angle of attack is too high, stall is observed in the annular stator blade row 6. This stall results in a high level of pressure loss and significant gyration, thereby reducing the propulsion efficiency of the propeller 4.

[0044] Therefore, the angle of attack must be kept within an acceptable range defined by the aerodynamic stability of the profile used, which is known at the time of its design. Furthermore, there exists an optimal angle of attack for which the performance of the annular stator blade row 6 is maximized. To optimize the performance of the propulsion system 1, it is therefore necessary to approach this angle of attack throughout the entire flight phase. Therefore, the angle setting β2 applied to the annular stator blade row 6 must be determined by this angle. control.

[0045] Therefore, this document provides an effective way to combine the parameters affecting the aerodynamics of the propeller 4 and the annular stator blade array 6 in order to determine the aerodynamics of only two parameters, namely the angle. The angle setting β2 of the annular stator blade row 6 is related to the Mach number 10 variation of the airflow incident on the propeller 4.

[0046] Figure 3 The illustration shows a schematic diagram of a method for determining the angle setting β1 of the propeller 4 and the angle setting β2 of the annular stator blade row 6 downstream of the propeller 4. This method 12 can be implemented in the calculator of the propulsion system (FADEC - "Full Authority Digital Engine Control").

[0047] The method 12 includes a first step of establishing a theoretical model 14 of the propeller 4. For this purpose, the power P1 and mechanical velocity N1 associated with the propeller, along with flight conditions 16, are used as inputs to the theoretical model of the propeller. The flight conditions include the velocity V0 of the airflow incident on the propeller, the altitude of the propulsion system, and the ambient temperature. This theoretical model 14 of the propeller 4 determines the angle setting β1 of the propeller 4. The propeller is thus modeled using this theoretical model, which is in tabular form and includes multiple velocities V0 for the incident airflow, the advance ratio J1 defined for the multiple angle settings β1 of the propeller 4, and the power coefficient C. p,1 and tension system C T,1 The output of the theoretical model 14 for the propeller includes at least the power coefficient C of the propeller 4. p,1 Tensile coefficient CT,1 The dimensionless parameter 17 of the advance ratio J1 can be used and will be defined by the following formula:

[0048]

[0049]

[0050]

[0051] Where ρ corresponds to the density of ambient air, V0 corresponds to the flight speed of the propulsion system, N1 corresponds to the mechanical speed of the propeller, D1 corresponds to the diameter of the propeller, P1 corresponds to the power of the propeller, and T1 corresponds to the thrust of the propeller.

[0052] These dimensionless parameters 17 associated with the propeller 4 are then transmitted to the configuration model of the annular stator blade array 18, such as... Figure 5 As shown in the figure. In fact, according to the dimensionless parameter 17, the longitudinal velocity V iz and tangential component V iθ Based on longitudinal velocity V iz Froude's law of conservation of momentum and the tangential component V iθ The calculation is based on Euler's law. The two velocities V... iz and V iθ Follow the following relationship:

[0053]

[0054] Where K1 is a constant related to the radial dimension of the propeller 4, and:

[0055]

[0056] K1 and K2 are constants related to the radial dimension of the propeller 4.

[0057] Then, based on the following relationship: According to the longitudinal velocity V iz and tangential component V iθ Obtain the angle

[0058] Pre-build database 20. It allows for each angle It is associated with different angle settings of β2 for the annular stator blade row 6 obtained for different Mach numbers.

[0059] To implement the database 20, the tension coefficient C′ of the straightening machine is calculated according to the following formula. T,2 :

[0060]

[0061] Where D2 corresponds to the diameter of the annular stator blade row 6, T2 corresponds to the tension of the annular stator blade row 6, and V2 corresponds to the velocity received by the annular stator blade row 6. This tension coefficient is needed to create the database.

[0062] The database contains information on each Mach number and angle. A table relating the values ​​of the angle setting β2 of the annular stator blade row 6. This database was constructed through simulation or testing. Several operating conditions associated with all combinations of parameters were calculated. The parameters considered are: rotor speed N1, flight Mach number, angle setting β1 of the propeller 4, and angle setting β2 of the annular stator blade row 6. For each of these operating points, the angle was calculated. and tensile coefficient C′ T,2 This gives the change with flight Mach number and angle. The tension coefficient C′ varies with β2 at the angle of the annular stator blade row 6. T,2 The table. For each flight Mach number and angle in this table. Choose to select coefficient C′ T,2 The angle setting β2 of the 6th row of annular stator blades is maximized. Therefore, the value of β2 is obtained by using the Mach number and angle... The control law is in the form of β2, which sets the angle of the 6th row of annular stator blades.

[0063] The database creation described above allows for the rapid and simple determination of the optimal value for the angle setting β2 applied to the annular stator blade row. This database can be integrated into the memory unit of the FADEC without requiring additional complex computational components.

[0064] According to this database 20, the angle mentioned And the Mach number 10 associated with the velocity of the airflow incident on the propeller, determines the angle setting β2 to be applied to the annular stator blade row 6.

[0065] Finally, the angle setting β2 of the annular stator blade row 6 is transmitted by the FADEC system to the actuator, which controls the setting of the annular stator blade row 6. The system and logic provided herein make determining the angle setting β2 of the annular stator blade row easier to implement, more robust to changes in flight conditions 16, and easier to store in the FADEC, because method 12 requires less data. Due to this determination of the angle setting β2, the annular stator blade row 6 always provides optimal thrust for a given flight phase.

Claims

1. An angular arrangement for determining the row of annular stator blades (6) downstream of the propeller (4) of the propulsion system (1) having a longitudinal axis (2). The method involves the annular stator blade array (6) receiving an airflow having a velocity V2, the velocity including a longitudinal component V. iz and the tangential component associated with the rotational speed generated by the propeller (4). The method includes the following steps: a) establishing a theoretical model (14) of the propeller (4) using the power PI and the mechanical speed Nl associated with the propeller (4) and flight conditions (16) including the speed of the airflow incident on the propeller, the height of the propulsion system (1) and the ambient temperature; b) determining an angular setting of the propeller (4) in accordance with the theoretical model (14) ; c) Based on the theoretical model (14) of the propeller (4), define a dimensionless parameter (17) that includes at least the power coefficient C of the propeller (4) as defined by the following formula. p,1 Tensile coefficient C T,1 And approach ratio J1: wherein p corresponds to the density of the ambient air, V0 corresponds to the flight speed of the propulsion system, N1 corresponds to the mechanical speed of the propeller, D1 corresponds to the diameter of the propeller, PI corresponds to the power of the propeller, T1 corresponds to the pull of the propeller, d) calculating the longitudinal component V of the velocity V2 of the air flow incident on the annular stator blade row (6) as a function of the said dimensionless parameter (17) iz and the tangential component and deriving the angle between the velocity of the air flow incident on the annular stator blade row (6) and the plane of rotation (8) of the pusher propeller (4) ; e) determining the angular setting to be applied to the annular stator blade row (6) as a function of the angle , of the Mach number (10) associated with the speed of the airflow incident on the propeller (4) and of the database (20) associated with each angle . The angular setting of the annular stator blade row (6) is determined as a function of the angle , of the Mach number (10) associated with the speed of the airflow incident on the propeller (4) and of the database (20) associated with each angle . Different angular settings of the annular stator blade row (6) are obtained for different Mach numbers (10).

2. The method of claim 1, wherein, The longitudinal component V2 of the velocity V2 of the air flow incident on the annular stator blade row (6) is calculated according to the following formula iz : wherein K1 is a constant related to the radial dimension of the propeller (4).

3. The method according to claim 1 or 2, characterized in that, The tangential component of the velocity V2 of the airflow incident on the annular stator blade row (6) is calculated according to the following formula : wherein K1 and K2 are constants related to the radial dimension of the propeller (4).

4. The method according to claims 1 to 3, characterized in that, the angle complies with the following equation: 。 5. The method according to any of the preceding claims, characterized in that, setting the angle of the annular stator vane row (6) by a FADEC system communicating to an actuator, which controls the angle setting of the annular stator vane row (6) .

6. The method according to any of the preceding claims, characterized in that, The database (20) is a table constructed through simulation or testing, based on parameters selected from: rotor speed N1, flight Mach number, and the angle setting of the propeller (4). The angle setting of the annular stator blade row (6) All combinations of calculations are performed under multiple operating conditions to determine the relationship between the flight Mach number and angle. The angle setting of the annular stator blade row (6) Maximum variation of tensile force coefficient The table.

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