Position optimization method for paddle fan shaft handle of open rotor engine

Abstract

The invention provides a position optimization method for a paddle fan shaft handle of an open type rotor engine. The position optimization method comprises the steps that S1, the position of the paddle fan shaft handle, paddle fan pitch angles of all working condition points and aerodynamic loads are input; inputting parameters of the paddle fan; s2, constructing a fitness function, constructing constraint conditions and establishing an optimization function by taking a propeller fan translation vector and a propeller fan rotation angle at a propeller pitch angle beta0 as optimization variables; s3, carrying out optimization calculation by adopting a single-target or multi-target optimization algorithm, and outputting an optimal blade fan position; s4, setting a moving position of a pitch angle lower shaft handle, and substituting the moving position into the pneumatic finite element calculation model to calculate propeller fan pneumatic loads of all working condition points; and S5, judging whether the error between the aerodynamic load and the aerodynamic load adopted in the optimization calculation process meets the requirement or not. According to the blade fan shaft handle position optimization method provided based on blade fan aerodynamic load, centrifugal load and friction load calculation formulas, the number of times of calculation of the aerodynamic load in the optimization process is effectively reduced, and the blade fan shaft handle position optimization efficiency is improved.

Description

Technical Field

[0001] The invention relates to the field of open rotor engines, and in particular to a method for optimizing the position of a propeller shaft handle of an open rotor engine. Background Art

[0002] In the prior art, open rotor engines rely on a variable pitch system to adjust the pitch angle of the propeller, so that the blades in different working states can work at a suitable angle of attack of the incoming flow, thereby improving working efficiency. In the process of adjusting the pitch angle, the variable pitch system needs to overcome the torque generated by the aerodynamic load, centrifugal load and friction load of the propeller. On the other hand, the aerodynamic and centrifugal loads will also generate a bending moment perpendicular to the shaft direction, which will bring a large load to the propeller support bearing.

[0003] However, the magnitude of these torque and bending moment loads is related to the position of the propeller shaft handle. Therefore, by optimizing the position of the propeller shaft handle, the load of the variable pitch system adjustment and the load of the propeller shaft handle support bearing can be effectively reduced.

[0004] In fact, the propeller fan load under different flight conditions is affected by many factors such as rotation speed, pitch angle, and incoming flow velocity, which brings challenges to the optimization efficiency of the shaft handle position. Therefore, considering the propeller fan load under various flight conditions and establishing an efficient propeller fan shaft handle position optimization method is of great significance to improving the variable pitch system and the propeller fan shaft handle bearing load.

[0005] The optimization objectives of the propeller shaft position of an open rotor engine are mainly: the adjustment load of the variable pitch system and the load of the supporting bearing of the propeller shaft. However, these loads are not only related to the propeller shaft position, but also affected by factors such as the speed, pitch angle, and incoming flow velocity under flight conditions. After modifying the propeller shaft position, it is usually necessary to recalculate using finite element software or dynamics software, which seriously restricts the optimization efficiency of the propeller shaft position.

[0006] In view of this, the inventor of the present application has designed a method for optimizing the position of a propeller shaft handle of an open rotor engine in order to overcome the above-mentioned technical problems. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the defect in the prior art that the load of the propeller shaft handle of an open rotor engine is affected by factors such as the rotational speed, pitch angle, incoming flow velocity under aircraft operating conditions, and requires finite element software or dynamics software to be recalculated, which seriously restricts the efficiency of optimizing the position of the propeller shaft handle. A method for optimizing the position of the propeller shaft handle of an open rotor engine is provided.

[0008] The present invention solves the above technical problems through the following technical solutions:

[0009] A method for optimizing the position of a propeller shaft of an open rotor engine, wherein the method comprises the following steps:

[0010] S 1 , input the position of the propeller shaft, as well as the propeller pitch angle and aerodynamic load F at all operating points a (β), M a (β); Input propfan parameters;

[0011] S 2 , with pitch angle β 0 Lower propeller translation vector P d (β 0 ), pitch angle β 0 The angle of rotation of the propeller fan around the Ox axis To optimize the variables, construct the fitness function f(F t (β),M t (β)), construct constraint conditions and establish optimization function;

[0012] S 3 , for the step S 2 The established optimization function uses a single-objective or multi-objective optimization algorithm to perform optimization calculations and output the pitch angle β of the optimal propeller fan position. 0 Lower propeller translation vector P d (β 0 ), the angle of rotation of the propeller around the Ox axis

[0013] S 4 , set the pitch angle β 0 The moving position of the lower shaft handle is -P d (β 0 ), Substitute the aerodynamic finite element calculation model to calculate the propeller aerodynamic load F′ at all working points a (β), M′ a (β);

[0014] S 5 , Determine the aerodynamic load F′ a (β), M′ a (β) and the aerodynamic load F used in the optimization calculation process a (β), M a Whether the error between (β) meets the requirements;

[0015] If the requirements are not met, the aerodynamic load used in the optimization calculation process is set to F′ a (β), M′ a (β), jump to step S 2 ;

[0016] If the requirements are met, the output optimal propeller shaft position is -P d (β 0 ),

[0017] Where β represents the pitch angle of other non-design point conditions; β 0 P represents the pitch angle of the design point condition; d (β 0 ) Pitch angle β 0 Lower propeller translation vector.

[0018] According to one embodiment of the present invention, the step S 1 The parameters of the propeller fan include: propeller fan mass, center of mass, product of inertia, and moment of inertia.

[0019] According to one embodiment of the present invention, the position optimization method further comprises calculating aerodynamic loads:

[0020] The aerodynamic pressure of the propeller fan is obtained by flow field calculation under the design operating point. The aerodynamic pressure of the blade is integrated at the aerodynamic integration point to obtain the aerodynamic force and aerodynamic moment acting on the point as F. a (β 0 )、M a (β 0 );

[0021] The aerodynamic integration point is selected as the center point of the propeller shaft support bearing of the current design, and the aerodynamic integration point is located on the z-axis;

[0022] The propeller fan moves along the vector P d (β 0 ) after translation, it can be assumed that the aerodynamic pressure distribution on the propeller fan surface remains unchanged, then the aerodynamic force and aerodynamic moment on point P' are still F a (β 0 )、M a (β 0 );

[0023] The load on the bearing support center point is calculated using the following formula:

[0024]

[0025] For the non-design point working condition, the propeller fan after translation still moves from the pitch angle β around the original support bearing center Oz axis. 0 Rotate to β, the propeller translation vector P d (β 0 ) is transformed into P d (β), then the load on the bearing support center point is calculated by the following formula:

[0026]

[0027] Among them, P d (β) is the propeller fan movement vector under the pitch angle β, that is, P d (β 0 ) rotates around the original support bearing center Ox axis (β-β 0 ) is calculated by the following formula:

[0028]

[0029] According to one embodiment of the present invention, the position optimization method further comprises calculating the centrifugal load:

[0030]

[0031]

[0032]

[0033]

[0034] Among them, the inertia I xz ,I yz And the moment of inertia I yy ,I xx It should be solved when the propeller fan mass center is translated to the Oz axis; The propeller fan pitch angle is β 0 When the centroid of the propeller moves along the Ox and Oy directions to the Oz axis, and then moves along the vector P d (β 0 ) translation, the components of the translation vector along the Ox, Oy, and Oz directions of the entire process; M cx 、M cy 、M cz It represents the centrifugal moment of the propeller about the initial bearing center point B along the Ox, Oy, and Oz directions in the Oxyz inertial coordinate system.

[0035] According to one embodiment of the present invention, the position optimization method further includes calculating the friction torque:

[0036]

[0037] Where μ is the bearing friction coefficient, d p is the average bearing diameter, F c It is the centrifugal force acting on a mass point on the propeller or blade.

[0038] According to one embodiment of the present invention, the total load on the propeller shaft support bearing center point B is:

[0039]

[0040] According to one embodiment of the present invention, the position optimization method further includes circumferential position adjustment:

[0041] Establish a rotating coordinate system Ox′y′z′, whose Oz′ axis always coincides with the axis of bearing B′;

[0042] Bearing B' initially coincides with bearing B. When the propeller rotates along the Ox axis, bearing B' will rotate with the propeller.

[0043] The load F on bearing B' in the rotating coordinate system Ox′y′z′ t (β)′、M t (β)′ will always remain unchanged, and the load on bearing B can be obtained by first converting the load on bearing B′ into the inertial coordinate system Oxyz and then calculating it through the translation of the force.

[0044] The positive and progressive effects of the present invention are:

[0045] The method for optimizing the position of the propeller shaft handle of an open rotor engine of the present invention has the following advantages:

[0046] 1. The established calculation model of propeller fan aerodynamic load, centrifugal load and friction load changing with propeller fan position effectively shortens the load calculation time required for propeller fan shaft optimization;

[0047] 2. The propeller shaft handle position optimization method proposed based on the calculation formulas of propeller aerodynamic load, centrifugal load and friction load can effectively reduce the number of calculations of aerodynamic loads in the optimization process and improve the efficiency of propeller shaft handle position optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always represent the same features, wherein:

[0049] Figure 1 The present invention is a flow chart of a method for optimizing the position of a propeller shaft handle of an open rotor engine.

[0050] Figure 2 It is a schematic diagram of the position adjustment of the propeller along the Ox and Oy directions in the method for optimizing the position of the propeller shaft handle of the open rotor engine of the present invention.

[0051] Figure 3 In the method for optimizing the position of a propeller shaft handle of an open rotor engine of the present invention, the circumferential position of the propeller is adjusted.

[0052] Figure 4 It is a schematic diagram of the propeller translation vector under non-design conditions in the method for optimizing the position of the propeller shaft handle of the open rotor engine of the present invention.

[0053] Figure 5 It is a schematic diagram of the centrifugal load of the propeller fan in the method for optimizing the position of the propeller fan shaft handle of the open rotor engine of the present invention. DETAILED DESCRIPTION

[0054] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0055] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Reference will now be made in detail to preferred embodiments of the present invention, examples of which are shown in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to represent the same or similar parts.

[0056] Furthermore, although the terms used in the present invention are selected from well-known and commonly used terms, some terms mentioned in the present invention specification may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this document.

[0057] Furthermore, it is required that the present invention be understood not only by the actual terms used but also by the meanings connoted by each term.

[0058] like Figures 1 to 5 As shown, the present invention discloses a method for optimizing the position of a propeller shaft handle of an open rotor engine. Aiming at the optimization demand for the position of a propeller shaft handle of an open rotor engine, based on the established calculation model of the propeller aerodynamic load, centrifugal load, and friction load changing with the propeller position, the method comprises the following steps:

[0059] Step S 1 , input the position of the propeller shaft, as well as the propeller pitch angle and aerodynamic load F at all operating points a (β), M a (β); Input propfan parameters.

[0060] Wherein, the step S 1 The parameters of the propeller fan include: propeller fan mass, center of mass, product of inertia, moment of inertia and other parameters.

[0061] Step S 2 , with pitch angle β 0 Lower propeller translation vector P d (β 0 ), the angle of rotation of the propeller fan around the Ox axis To optimize the variables, construct the fitness function f(F t (β),M t (β)), construct constraint conditions and establish optimization function.

[0062] Preferably, the fitness function f(F t (β),M t (β)), combined with the position movement range and other construction constraints, thus establishing the optimization function.

[0063] Among them, F t (β),M t (β) can be calculated by the following formula:

[0064]

[0065] Step S 3 , for the step S 2 The established optimization function uses a single-objective or multi-objective optimization algorithm to perform optimization calculations and output the pitch angle β of the optimal propeller fan position. 0 Lower propeller translation vector P d (β 0 ), pitch angle β 0 The angle of rotation of the propeller fan around the Ox axis

[0066] Step S 4 , set the pitch angle β 0 The moving position of the lower shaft handle is -P d (β 0 ), Substitute the aerodynamic finite element calculation model to calculate the propeller aerodynamic load F′ at all working points a (β), M′ a (β).

[0067] Step S 5 , Determine the aerodynamic load F′ a (β), M′ a (β) and the aerodynamic load F used in the optimization calculation process a (β), M a Whether the error between (β) meets the requirements;

[0068] If the requirements are not met, the aerodynamic load used in the optimization calculation process is set to F′ a (β), M′ a (β), jump to step S 2 ;

[0069] If the requirements are met, the output optimal propeller shaft position is -P d (β 0 ), That is to say, the optimization result is the pitch angle β 0 The propeller shaft handle is first adjusted along the Ox and Oy directions respectively -r xd、-r yd , and then adjust the angle along the circumferential position

[0070] Where β represents the pitch angle of other non-design point conditions; β 0 P represents the pitch angle of the design point condition; d (β 0 ) Pitch angle β 0 Lower propeller translation vector.

[0071] According to the above step description, the following is further described in detail with reference to the accompanying drawings:

[0072] Given the initial position of the propeller shaft handle at the design operating point, the propeller shaft handle position optimization variables include the design operating point shaft handle circumferential position, axial position and tangential position adjustment. However, the propeller shaft handle position optimization actually changes the relative position between the shaft handle and the propeller, so it can be assumed that the shaft handle position remains unchanged while the propeller position changes during calculation.

[0073] like Figure 2 As shown, the Oxyz inertial coordinate system is established according to the right-hand rule, with the engine axis as the x-axis and the propeller shaft support bearing axis as the z-axis. Figure 2 The position of the propeller fan is adjusted along the Ox and Oy directions, corresponding to the axial and tangential position adjustment of the shaft handle. Figure 3 The circumferential position adjustment of the propeller corresponds to the circumferential position adjustment of the shaft handle.

[0074] Figure 2 and Figure 3 In the figure, B represents the bearing support center point; F a represents the aerodynamic force acting on point P; represents the aerodynamic force acting on point B; M a represents the aerodynamic torque acting on point P; It represents the aerodynamic torque acting on point B; M z Represents the centrifugal torque acting on point B; M x represents the centrifugal bending moment acting on point B along the Ox direction; M y represents the centrifugal bending moment acting on point B along the Oy direction; P represents the aerodynamic integration point, which does not change with the rotation of the propeller; P d (β 0 ) represents the pitch angle β 0 Lower propeller fan movement vector.

[0075] The following is a detailed description of the propeller load calculation under different position adjustments:

[0076] like Figure 2 As shown, the propeller fan is adjusted in position along the Ox and Oy directions.

[0077] 1. Aerodynamic load calculation

[0078] like Figure 2 As shown in the figure, under the design operating point (pitch angle, incoming flow velocity and other factors are known), the aerodynamic pressure of the propeller fan is obtained by flow field calculation. The aerodynamic pressure of the blade is integrated about point P to obtain the aerodynamic force and aerodynamic moment acting on the point, which are F respectively. a (β 0 )、M a (β 0 ). Point P is fixed in the inertial coordinate system Oxyz and does not change with the rotation of the propeller.

[0079] Generally, point P is selected as the center point of the propeller shaft support bearing of the current design. At this time, point P is located on the z-axis. d (β 0 ) after translation, it can be assumed that the aerodynamic pressure distribution on the propeller fan surface remains unchanged, then the aerodynamic force and aerodynamic moment on point P' are still F a (β 0 )、M a (β 0 ).

[0080] At this time, the load on point B can be calculated by the following formula 1:

[0081]

[0082] For the pitch angle β of the non-design point working condition, the propeller fan after translation still moves from the pitch angle β around the original support bearing center Oz axis. 0 Rotate to β, such as Figure 3 As shown, the propeller translation vector P d (β 0 ) is transformed into P d (β), then the load on the bearing support center point is calculated by the following formula 2:

[0083]

[0084] Among them, P d (β) is the propeller fan movement vector under the pitch angle β, that is, P d (β 0 ) rotates around the original support bearing center Oz axis (β-β 0 ) is calculated by the following formula 3:

[0085]

[0086] 2. Centrifugal load calculation

[0087] like Figure 4 As shown, for a mass point m on the blade iWhen the engine rotates along Ox, it will be subjected to centrifugal force along the directions of Oy and Oz, thus generating centrifugal force, centrifugal torque and centrifugal bending moment on the bearing support point B.

[0088] The centrifugal force can be calculated by the following formula 4:

[0089]

[0090] Note that the propeller shaft support bearing center r xB =r yB =0, then the centrifugal moment at point B is calculated by the following formula 5:

[0091]

[0092] Design operating point propeller fan along vector P d (β 0 )=[r xd r yd r zd ] T After translation, when the propeller rotates around the original support bearing center to the pitch angle β, the mass point m i Position i (β) is calculated by the following formula 6:

[0093]

[0094] Among them, β * =β-β 0 , r i (β 0 )=[r xi r yi r zi ] T , R z (β * ) is the coordinate transformation matrix for rotation around the Oz axis.

[0095]

[0096] Substituting Equation 6 into Equation 4, we consider a propeller with a mass of m and a center of mass of [r xc r yc r zc ] T , we can get the centrifugal force when the propeller fan turns to pitch angle β:

[0097]

[0098] Similarly, substituting Formula 6 into Formula 5, we can obtain the centrifugal moment M at the center point B of the propeller shaft support bearing when the propeller rotates to the pitch angle β: c(β) Components along the three directions of Ox, Oy, and Oz:

[0099]

[0100]

[0101]

[0102] Among them, the inertia I xz =∑m i r xi r zi , I yz =∑m i r yi r zi .

[0103] In order to further simplify Formula 9, the following changes are made. 0 When the blade pitch angle β is β, the blade center of mass is first translated along the Ox and Oy directions to the Oz axis, which is used as the blade pitch angle β. 0 The initial state position, at this time the center of mass Then relative to the initial position, the pitch angle β 0 Lower propeller fan movement vector It can be calculated as:

[0104]

[0105] When considering the optimization of the propeller shaft, the propeller only moves in the Ox and Oy directions. zd = 0. At this time, Formula 8 and Formula 9 are simplified to:

[0106]

[0107]

[0108]

[0109]

[0110] At this time, the inertia product I in formula 11 xz ,I yz And the moment of inertia I yy ,I xx The solution should be obtained when the center of mass of the propeller fan is translated to the Oz axis. These variables can be obtained by assigning mass in the three-dimensional model and then measuring it.

[0111] 3. Friction torque calculation

[0112] Since the centrifugal force and aerodynamic force cause the propeller to generate positive pressure on the bearing, the propeller will be affected by the bearing friction torque during the adjustment process. Considering that the centrifugal force load is much greater than the aerodynamic force, the bearing friction torque is calculated according to the centrifugal force. The calculation method is as follows:

[0113]

[0114] Where μ is the bearing friction coefficient, d p is the average bearing diameter.

[0115] 4. Total load calculation

[0116] By summing the aerodynamic load, centrifugal load, and friction load, we can obtain the total load on point B at the center of the propeller shaft support bearing, as shown in Formula 13:

[0117]

[0118] Among them, sign() is a sign function, which is used to extract the positive and negative signs of the values ​​in brackets.

[0119] like Figure 3 As shown, the propeller fan circumferential position adjustment:

[0120] A rotating coordinate system Ox′y′z′ is established, and its Oz′ axis always coincides with the axis of bearing B'. Bearing B' initially coincides with bearing B. When the propeller rotates along the Ox axis, bearing B' will rotate with the propeller.

[0121] Therefore, the load F on bearing B' in the rotating coordinate system Ox'y'z' is t (β)′、M j (β)′ will always remain unchanged, that is, F t (β), M t (β).

[0122] At this time, the load of bearing B can be obtained by first converting the load of bearing B' into the inertial coordinate system Oxyz, and then calculating the force translation. The detailed calculation formula 14 is as follows:

[0123]

[0124] The load F of bearing B' in the rotating coordinate system is t (β)′、M t (β)′ can be calculated using formula 13.

[0125] In the above calculation process, the propeller fan first translates along the Oxy plane and then rotates along the Ox axis. is the rotation angle of the propeller around the Ox axis, is the coordinate transformation matrix rotating around the Ox axis, which can be calculated by formula 15:

[0126]

[0127] Then BB' can be calculated as

[0128]

[0129] Where I is the identity matrix.

[0130] According to the above content, the propeller shaft position optimization method can be quickly calculated according to formula 14 to obtain the propeller fan first adjust the position along the Ox and Oy directions r xd 、r yd , and then adjust the angle along the circumferential position Finally, the resultant force and moment of the aerodynamic, centrifugal and friction loads on the original supporting bearing are obtained. The moment along the Oz direction is the load that the variable pitch system needs to overcome, and the resultant force and moment in other directions are the loads on the propeller shaft support bearing.

[0131] Considering the relative relationship between the propeller and the shaft position, the load calculated by formula 12 and formula 13 is: The propeller shaft position is first adjusted along the Ox and Oy directions respectively -r xd 、-r yd , and then adjust the angle along the circumferential position Afterwards, the original propeller exerts load on the propeller shaft support bearing and variable pitch system.

[0132] Therefore, according to Formula 14, the loads of the propeller shaft support bearing and the variable pitch system after the propeller shaft position is adjusted can be quickly calculated. Therefore, according to the optimization objectives of the propeller shaft support bearing and the variable pitch system load, a multi-objective or single-objective optimization algorithm can be used to quickly obtain the optimized position of the propeller shaft.

[0133] Then, the aerodynamic loads of all working points are recalculated and corrected at the current position. If the optimization target is met, the optimized propeller shaft handle position is output. If the target is not met, the propeller shaft handle position is reoptimized according to the corrected aerodynamic load. This method can effectively reduce the number of calculations of aerodynamic loads during the optimization process, and can directly calculate the centrifugal load, thereby improving the optimization efficiency of the propeller shaft handle position.

[0134] According to the above description, the parameters involved in the method for optimizing the position of the propeller shaft of an open rotor engine of the present invention are listed as follows:

[0135] What the parameters mean

[0136] B: Initial bearing center point

[0137] B′: The center point of the bearing, which coincides with B at the beginning, and then rotates along the Ox axis with the propeller. angle

[0138] BB′: The vector of the bearing center point B′ relative to the initial bearing center point B

[0139] d p : Average bearing diameter

[0140] F a : The aerodynamic force acting on point P

[0141] The aerodynamic force acting on point B

[0142] F c : The centrifugal force on a mass point on a propeller or blade

[0143] F t : Consider the propeller fan at the initial pitch angle β 0 After translation, the propeller shaft support bearing center point B is The total force, including aerodynamic force, friction force, centrifugal force

[0144] F t (β)′: When the pitch angle is β, the total force on bearing B′ in the coordinate system Ox′y′Z′ includes Aerodynamics, friction, centrifugal force

[0145] Consider the propeller fan at the initial pitch angle β 0 After translation and adjustment of the circumferential position, the propeller shaft handle supports The total force acting on the bearing center point B, including aerodynamic force, friction force, centrifugal force

[0146] I yz ,I xz ,I xy The inertial product of the propeller about the center of mass along the Ox, Oy, and Oz directions in the Oxyz inertial coordinate system

[0147] I xx ,I yy ,I zz Inertial moments of the propeller about the center of mass in the Ox, Oy, and Oz directions in the Oxyz inertial coordinate system

[0148] m i The mass of a certain point on the blade

[0149] M a The aerodynamic torque acting on point P

[0150] The aerodynamic torque acting on point B

[0151] M c The centrifugal moment of a mass point on the propeller or blade about the initial bearing center point B

[0152] M f Bearing friction torque

[0153] M t Consider the propeller fan at the initial pitch angle β 0 After translation, the propeller shaft support bearing center point B is The total torque, including aerodynamic torque, friction torque, centrifugal torque

[0154] M t (β)′ is the total torque acting on bearing B′ in the coordinate system Ox′y′z′ when the pitch angle is β, Including aerodynamic torque, friction torque, centrifugal torque

[0155] Consider the propeller fan at the initial pitch angle β 0 After translation and adjustment of the circumferential position, the propeller shaft handle supports The total torque acting on the bearing center point B includes aerodynamic torque, friction torque, Centrifugal torque

[0156] M cx 、M cy 、M cz In the Oxyz inertial coordinate system, the propeller moves along the Ox, Oy, and Oz directions about the initial bearing center point B. Centrifugal torque

[0157] M x Centrifugal bending moment acting on point B along the Ox direction

[0158] M y Centrifugal bending moment along the Oy direction acting on point B

[0159] M z Centrifugal torque acting on point B in the direction of Oz

[0160] OB Initial bearing center point position vector

[0161] OP aerodynamic integration point position vector

[0162] Oxyz Inertial Coordinate System

[0163] Ox′y′z′ is a coordinate system that rotates with bearing B′, and its Oz′ axis always coincides with the axis of bearing B′

[0164] P Aerodynamic integration point, does not change with the rotation of the propeller fan

[0165] P d Propeller translation vector

[0166] P d (β) The blade translation vector at pitch angle β, i.e. P d (β 0 ) rotates around the original support bearing center Oz axis Motion (β-β 0 ) after the vector

[0167] P d (β 0 ) Pitch angle β 0 Lower propeller translation vector

[0168] The propeller pitch angle is β 0 When the centroid of the propeller moves along the Ox and Oy directions to the Oz axis, and then Vector P d (β 0 ), the translation vector of this whole process

[0169] r i The position vector of a mass point on the blade

[0170] r xB 、r yB 、r zB Coordinates of the initial bearing center point along the Ox, Oy, and Oz directions in the Oxyz inertial coordinate system

[0171] r xc 、r yc 、r zc Coordinates of the propeller fan mass center along the Ox, Oy, and Oz directions in the Oxyz inertial coordinate system

[0172] The propeller pitch angle is β 0 When the centroid of the propeller moves along the Ox and Oy directions to the Oz axis, Coordinates of the propeller fan's center of mass along the Ox, Oy, and Oz directions

[0173] r xd 、r yd 、r zd Pitch angle β 0 Lower propeller translation vector P d (β 0 ) components along the Ox, Oy, and Oz directions

[0174] The propeller pitch angle is β 0When the centroid of the propeller moves along the Ox and Oy directions to the Oz axis, and then Vector P d (β 0 ), the components of the translation vector along the Ox, Oy, and Oz directions of the entire process

[0175] r xi 、r yi 、r zi The coordinates of a mass point on the blade along the Ox, Oy, and oz directions in the Oxyz inertial coordinate system

[0176] R x , R y , R z Coordinate transformation matrix for rotation around the Ox, Oy, and Oz axes

[0177] β Pitch angle of other non-design point conditions

[0178] β 0 Design point working condition pitch angle

[0179] β * Pitch increment of other non-design point conditions relative to the design point conditions

[0180] μ Bearing friction coefficient

[0181] ω Angular velocity of the propeller around the engine axis

[0182] Pitch angle β 0 The angle of rotation of the propeller fan around the Ox axis

[0183] Aiming at the problem of optimizing the position of the propeller shaft of an open rotor engine, the present invention has the following innovative features:

[0184] 1. The calculation formulas for the resultant force and resultant torque of the propeller centrifugal load acting on the center point of the propeller shaft support bearing are derived. This can quickly calculate the load of the propeller centrifugal load on the variable pitch system and propeller support bearing at different rotation speeds and pitch angles, thereby improving the calculation efficiency of the centrifugal load after the shaft position is optimized.

[0185] Second, under the assumption that the aerodynamic pressure distribution does not change with the adjustment of the propeller shaft position, the formula for calculating the resultant force and torque of the centrifugal, aerodynamic, and friction loads on the propeller shaft support center after the propeller shaft position is optimized is derived. Among them, the propeller shaft position optimization variables include axial, tangential, and circumferential position adjustments, which improves the calculation efficiency of the resultant force and torque of the support center after the propeller shaft position is optimized.

[0186] 3. A propeller shaft handle position optimization method is proposed. Based on the centrifugal load theoretical formula and the calculation formulas for the resultant force and torque of the propeller shaft handle support center point after the shaft handle position is optimized, the propeller shaft handle support bearing and the variable pitch system load optimization target corresponding to the optimized shaft handle position are quickly calculated, and the aerodynamic load corresponding to the optimized output shaft handle position is corrected, which can effectively improve the optimization efficiency and accuracy of the propeller shaft handle position.

[0187] Therefore, the present invention proposes a method for optimizing the propeller shaft position of an open rotor engine, which can quickly calculate the variable pitch system adjustment load and the propeller shaft support bearing load under different flight conditions corresponding to the rotational speed, pitch angle, and incoming flow speed according to the propeller shaft position, thereby improving the optimization efficiency of the propeller shaft position.

[0188] In summary, the method for optimizing the position of the propeller shaft handle of an open rotor engine of the present invention has the following advantages:

[0189] 1. The established calculation model of propeller fan aerodynamic load, centrifugal load and friction load changing with propeller fan position effectively shortens the load calculation time required for propeller fan shaft optimization;

[0190] 2. The propeller shaft handle position optimization method proposed based on the calculation formulas of propeller aerodynamic load, centrifugal load and friction load can effectively reduce the number of calculations of aerodynamic loads in the optimization process and improve the efficiency of propeller shaft handle position optimization.

[0191] For those skilled in the art, the above invention disclosure is only used as an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary implementation of the present application.

[0192] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0193] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus facilitate the understanding of one or more embodiments of the invention, in the foregoing description of the embodiments of this application, multiple features are sometimes grouped into one embodiment, drawing, or description thereof. However, this disclosure method does not mean that the subject matter of this application requires more features than those mentioned in the claims. In fact, the features of an embodiment are less than all the features of a single embodiment disclosed above.

[0194] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A method for optimizing the position of a propeller shaft of an open rotor engine. It is characterized in that The location optimization method comprises the following steps: S 1 , input the position of the propeller shaft, as well as the propeller pitch angle and aerodynamic load F at all operating points a (β), M a (β); Input propfan parameters; S 2 , with pitch angle β 0 Lower propeller translation vector P d (β 0 ), the angle of rotation of the propeller fan around the Ox axis To optimize the variables, construct the fitness function f(F t (β), M t (β)), construct constraint conditions and establish optimization function; S 3 , for the step S 2 The established optimization function uses a single-objective or multi-objective optimization algorithm to perform optimization calculations and output the pitch angle β of the optimal propeller fan position. 0 Lower propeller translation vector P d (β 0 ), pitch angle β 0 The angle of rotation of the propeller fan around the Ox axis S 4 , set the pitch angle β 0 The moving position of the lower shaft handle is -P d (β 0 ), Substitute the aerodynamic finite element calculation model to calculate the propeller aerodynamic load F′ at all working points a (β), M′ a (β); S 5 and judge the aerodynamic load F′ a (β), M′ a (β) and the aerodynamic load F a (β), M a (β) to see if the error meets the requirements; If the requirements are not met, the aerodynamic load used in the optimization calculation process is set to F′ a (β), M′ a (β), jump to step S 2 ; If the requirements are met, the output optimal propeller shaft position is -P d (β 0 ), Where β represents the pitch angle of other non-design point conditions; β 0 P represents the pitch angle of the design point condition; d (β 0 ) Pitch angle β 0 Lower propeller translation vector.

2. The method for optimizing the position of the propeller shaft of an open rotor engine according to claim 1, It is characterized in that The step S 1 The parameters of the propeller fan include: propeller fan mass, center of mass, product of inertia, and moment of inertia.

3. The method for optimizing the position of the propeller shaft of the open rotor engine according to claim 1, It is characterized in that The position optimization method also includes the calculation of aerodynamic loads: The aerodynamic pressure of the propeller fan is obtained by flow field calculation under the design operating point. The aerodynamic pressure of the blade is integrated at the aerodynamic integration point to obtain the aerodynamic force and aerodynamic moment acting on the point as F. a (β 0 )、M a (β 0 ); The aerodynamic integration point is selected as the center point of the propeller shaft support bearing of the current design, and the aerodynamic integration point is located on the z-axis; The propeller fan moves along the vector P d (β 0 ) after translation, it can be assumed that the aerodynamic pressure distribution on the propeller fan surface remains unchanged, then the aerodynamic force and aerodynamic moment on point P' are still F a (β 0 )、M a (β 0 ); The load on the bearing support center point is calculated using the following formula: For the non-design point working condition, the propeller fan after translation still moves from the pitch angle β around the original support bearing center Oz axis. 0 Rotate to β, the propeller translation vector P d (β 0 ) is transformed into P d (β), then the load on the bearing support center point is calculated by the following formula: Among them, P d (β) is the propeller fan movement vector under the pitch angle β, that is, P d (β 0 ) rotates around the original support bearing center Oz axis (β-β 0 ) is calculated by the following formula:

4. The method for optimizing the position of the propeller shaft of an open rotor engine according to claim 1, It is characterized in that The position optimization method also includes the calculation of centrifugal loads: Among them, the inertia I xz ,I yz And the moment of inertia I yy ,I xx It should be solved when the propeller fan mass center is translated to the Oz axis; The propeller fan pitch angle is β 0 When the centroid of the propeller moves along the Ox and Oy directions to the Oz axis, and then moves along the vector P d (β 0 ) translation, the components of the translation vector along the Ox, Oy, and Oz directions of the entire process; M cx 、M cy 、M cz It represents the centrifugal moment of the propeller about the initial bearing center point B along the Ox, Oy, and Oz directions in the Oxyz inertial coordinate system.

5. The method for optimizing the position of the propeller shaft of an open rotor engine according to claim 1, It is characterized in that The position optimization method also includes the calculation of the friction torque: Where μ is the bearing friction coefficient, d p is the average bearing diameter, F c It is the centrifugal force acting on a mass point on the propeller or blade.

6. The method for optimizing the position of the propeller shaft of an open rotor engine according to claim 1, It is characterized in that The total load on the propeller shaft support bearing center point B is:

7. The method for optimizing the position of the propeller shaft of an open rotor engine according to claim 1, It is characterized in that The position optimization method also includes circumferential position adjustment: Establish a rotating coordinate system Ox′y′z′, whose Oz′ axis always coincides with the axis of bearing B′; Bearing B′ initially coincides with bearing B. When the propeller rotates along the Ox axis, bearing B′ will rotate with the propeller. The load F on bearing B′ in the rotating coordinate system Ox′y′z′ t (β)′、M t (β)′ will always remain unchanged, and the load of bearing B can be obtained by first converting the load of bearing B′ into the inertial coordinate system Oxyz and then calculating it through the translation of the force.

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