Component dynamic load estimation device and method considering rotor wing lower washing flow interference

Abstract

The invention provides a component dynamic load estimation device and method considering rotor wing lower washing flow interference, the device comprises a full-aircraft module, and the full-aircraft module comprises a main rotor wing module used for providing rotor wing blade airfoil parameters, rotor wing blade aerodynamic parameters and rotor wing blade structure parameters; the tail rotor module is used for providing tail rotor blade airfoil parameters, tail rotor blade aerodynamic parameters and tail rotor blade structure parameters; the horizontal tail module is used for providing horizontal tail dynamic characteristic data; the fuselage module is used for providing fuselage aerodynamic characteristic data, overall parameters and rotor wing downwash velocity distribution; the balancing analysis module is used for calculating to obtain a tail rotor dynamic load or a horizontal tail dynamic load; the method can effectively guide the strength check and life evaluation work of each part of the helicopter, can effectively guide the weight reduction and life prolonging of each part of the helicopter, reduces the flight accident rate, and improves the overall performance of the helicopter.

Description

Technical Field

[0001] The present application belongs to the technical field of rotorcraft component loads, and in particular, relates to a component dynamic load estimation device and method taking into account rotor downwash interference. Background Art

[0002] The dynamic load of helicopter components is a direct input for the strength verification and life assessment of helicopter components, and is also an important input for reducing weight and increasing life of all components of the entire aircraft. If the calculated dynamic load result is lower than the actual situation, it will cause damage to helicopter components during flight and cause flight accidents; if the calculated dynamic load result is higher than the actual situation, it will cause the weight of helicopter components to increase in order to meet the requirements, reducing the performance of the entire helicopter. Summary of the invention

[0003] Purpose of the invention: Since accurate prediction of dynamic loads on helicopter components is of great significance to helicopter design and development, the present application provides a component dynamic load prediction device and method taking into account rotor downwash interference.

[0004] In a first aspect, the present application provides a component dynamic load estimation device taking into account rotor downwash interference, wherein the component includes a helicopter tail rotor and a horizontal tail, and the device includes a whole-machine module, wherein the whole-machine module includes:

[0005] The main rotor module is used to provide rotor blade airfoil parameters, rotor blade aerodynamic parameters and rotor blade structural parameters;

[0006] A tail rotor module is used to provide tail rotor blade airfoil parameters, tail rotor blade aerodynamic parameters and tail rotor blade structural parameters;

[0007] The horizontal tail module is used to provide the aerodynamic characteristics data of the horizontal tail;

[0008] The fuselage module is used to provide fuselage aerodynamic characteristics data, overall parameters and rotor downwash velocity distribution;

[0009] The trim analysis module is used to calculate the tail rotor dynamic load or the horizontal tail dynamic load.

[0010] Preferably, the fuselage module comprises:

[0011] The fuselage flow field assembly is used to provide rotor downwash velocity distribution.

[0012] Preferably, the fuselage flow field component is embedded in the fuselage module in the form of an interference speed table file.

[0013] Preferably, the trim analysis module is further used to call the rotor blade airfoil parameters, rotor blade aerodynamic parameters, rotor blade structural parameters, tail rotor blade airfoil parameters, tail rotor blade aerodynamic parameters, tail rotor blade structural parameters, horizontal tail aerodynamic characteristic data, fuselage aerodynamic characteristic data, overall parameters and rotor downwash velocity distribution;

[0014] The trim analysis module is further used to adjust the rotor control amount, the tail rotor control amount, the horizontal tail rudder deflection angle and the fuselage attitude angle to perform six-force element trim of the entire aircraft based on the rotor blade airfoil parameters, the rotor blade aerodynamic parameters, the rotor blade structural parameters, the tail rotor blade airfoil parameters, the tail rotor blade aerodynamic parameters, the tail rotor blade structural parameters, the horizontal tail aerodynamic characteristic data, the fuselage aerodynamic characteristic data, the overall parameters and the rotor downwash velocity distribution, extract the aerodynamic load on the tail rotor or the horizontal tail that changes with time, further process the aerodynamic load, and calculate the tail rotor dynamic load or the horizontal tail dynamic load.

[0015] In a second aspect, the present application further provides a method for estimating dynamic loads of helicopter components taking into account rotor downwash interference, wherein the components include a helicopter tail rotor and a horizontal tail, and the method includes:

[0016] The main rotor module provides rotor blade airfoil parameters, rotor blade aerodynamic parameters and rotor blade structural parameters;

[0017] The tail rotor module provides tail rotor blade airfoil parameters, tail rotor blade aerodynamic parameters and tail rotor blade structural parameters;

[0018] The horizontal tail module provides the horizontal tail aerodynamic characteristic data;

[0019] The fuselage module provides fuselage aerodynamic characteristics data, overall parameters and rotor downwash velocity distribution;

[0020] The trim analysis module receives the rotor blade airfoil parameters, rotor blade aerodynamic parameters, rotor blade structural parameters, tail rotor blade airfoil parameters, tail rotor blade aerodynamic parameters, tail rotor blade structural parameters, horizontal tail aerodynamic characteristic data, fuselage aerodynamic characteristic data, overall parameters and rotor downwash velocity distribution, and further calculates the tail rotor dynamic load or the horizontal tail dynamic load.

[0021] Preferably, the fuselage module comprises a fuselage flow field component, and the fuselage flow field component is embedded in the fuselage module in the form of an interference speed table file.

[0022] Preferably, the method further comprises:

[0023] The fuselage flow field assembly provides the rotor downwash velocity distribution.

[0024] Preferably, the method further comprises:

[0025] The trim analysis module calls the rotor blade airfoil parameters, rotor blade aerodynamic parameters, rotor blade structural parameters, tail rotor blade airfoil parameters, tail rotor blade aerodynamic parameters, tail rotor blade structural parameters, horizontal tail aerodynamic characteristic data, fuselage aerodynamic characteristic data, overall parameters and rotor downwash velocity distribution;

[0026] The trim analysis module adjusts the rotor control amount, the tail rotor control amount, the horizontal tail rudder deflection angle and the fuselage attitude angle to perform six-force element trim of the whole aircraft based on the rotor blade airfoil parameters, the rotor blade aerodynamic parameters, the rotor blade structural parameters, the tail rotor blade airfoil parameters, the tail rotor blade aerodynamic parameters, the tail rotor blade structural parameters, the horizontal tail aerodynamic characteristic data, the fuselage aerodynamic characteristic data, the overall parameters and the rotor downwash velocity distribution, extracts the aerodynamic load on the tail rotor or the horizontal tail that changes with time, further processes the aerodynamic load, and calculates the tail rotor dynamic load or the horizontal tail dynamic load.

[0027] Beneficial technical effects of this application:

[0028] The present invention can achieve high-precision prediction of the dynamic loads of a helicopter tail rotor and horizontal tail, has broad application prospects, and is applicable to all helicopters currently in service and under development.

[0029] The present invention can effectively guide the strength verification and life assessment of various components of a helicopter, and can effectively guide the weight reduction and life increase of various components of a helicopter, thereby reducing the occurrence rate of flight accidents and improving the overall performance of the helicopter. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic diagram of the relative positions of the rotor downwash and the tail rotor under different flight states provided by an embodiment of the present application;

[0031] Figure 2 is a flow chart of a component dynamic load estimation method taking into account rotor downwash interference provided by an embodiment of the present application;

[0032] Figure 3 The interference speed table provided in the embodiment of the present application is

[0033] Figure 4 is a velocity field distribution diagram of the entire machine calculated by the computational fluid dynamics method provided in the embodiment of the present application;

[0034] Figure 5 It is a comparison chart of calculation and test results provided in the embodiments of the present application. DETAILED DESCRIPTION

[0035] See also Figure 1 and Figure 2 , the solution provided by the present invention includes the following contents:

[0036] (1) Main rotor modeling, including rotor blade airfoil parameter settings, rotor blade aerodynamic parameter settings, and rotor blade structural parameter settings. The rotor blade airfoil parameter settings include the aerodynamic data of each airfoil and the airfoil distribution along the blade span. The rotor blade aerodynamic parameter settings include the chord length and sweep angle distributed along the blade span.

[0037] The rotor blade structural parameter settings include the torsion angle, tensile stiffness, section moment of inertia, swing stiffness, flapping stiffness, torsional stiffness, linear mass distributed along the span direction of the blade, as well as the overall parameters of the rotor blade, such as the number of blades, rotation direction, tip speed, and hub type.

[0038] (2) Tail rotor modeling, including the setting of tail rotor blade airfoil parameters, tail rotor blade aerodynamic parameters and tail rotor blade structural parameters. The tail rotor blade airfoil parameter setting includes the aerodynamic data of each airfoil and the distribution of the airfoil along the blade span. The tail rotor blade aerodynamic parameter setting includes the chord length and sweep angle distributed along the blade span. The tail rotor blade structural parameter setting includes the torsion angle, tensile stiffness, section moment of inertia, swing stiffness, flapping stiffness, torsional stiffness, linear mass distributed along the blade span, and also includes the overall parameters of the tail rotor blade, such as the number of blades, rotation direction, tip speed, and hub type.

[0039] (3) Horizontal tail modeling, including the horizontal tail aerodynamic characteristics data. The horizontal tail aerodynamic characteristics data include the horizontal tail lift and horizontal tail drag that change with the angle of attack and sideslip angle.

[0040] (4) Fuselage modeling, including fuselage aerodynamic characteristic data and overall parameters. The fuselage aerodynamic characteristic data includes six necessary fuselage aerodynamic data files: lift, drag, side force, rolling moment, pitch moment, and yaw moment that change with the angle of attack and sideslip angle. Overall parameters include helicopter configuration, number of rotors, transmission ratio between rotors, fuselage weight, fuselage drag area, center of gravity position of the whole aircraft, and aerodynamic action nodes of each component.

[0041] (5) Obtain more accurate rotor downwash velocity distribution at the tail rotor and horizontal tail. This can be calculated using computational fluid dynamics methods or obtained through experimental measurements.

[0042] (6) Embedding of fuselage flow field components. The purpose is to change the rotor downwash velocity distribution at the tail rotor and horizontal tail calculated by the software itself. The fuselage flow field component is embedded in the form of an interference speed table file. The interference speed given in the interference speed table is centered on the center of the interfered tail rotor hub and is distributed in azimuth and radial positions in the plane of the actual position of the interfered tail rotor. The interference speed is in the fuselage coordinate system, and the positive direction of the interference speed is defined as: X forward, Y right, and Z downward. The first dimension of the interference speed table is the radial position, which is dimensionless and ranges from 0 to 1; the second dimension is the phase or time, and the phase unit is angle; the intermediate speed units are Vx / V, Vy / V, Vz / V; among them, Vx, Vy, Vz represent the interference speeds in three directions, and V represents the flight speed of the entire aircraft. The specific format is as follows Figure 3 shown.

[0043] (7) The whole machine modeling is now completed.

[0044] (8) Carry out full aircraft trim calculation analysis for specific flight conditions. Subsequent dynamic load calculations are based on the trim calculation results. The trim calculation settings mainly include trim targets, trim variables, trim calculation methods, and convergence control.

[0045] (9) Output of calculation results of the example.

[0046] (10) Post-processing to obtain dynamic loads. Generally, a small self-written program is used to extract key component dynamic load data from complex calculation results.

[0047] In other embodiments of the present application, the solutions provided by the present application are as follows:

[0048] (1) Determine the helicopter model. Here, a single-rotor helicopter with a tail rotor is used as an example. The rotor has three blades, the tail rotor has two blades, the fuselage is a ROB IN fuselage, the rotor tip speed is 210 m / s in hovering, and the flight speed is 21 m / s.

[0049] (2) Main rotor modeling, including rotor blade airfoil parameter settings, rotor blade aerodynamic parameter settings, and rotor blade structural parameter settings. The rotor blade airfoil parameter settings include the aerodynamic data of each airfoil and the distribution of the airfoil along the blade span. The rotor blade aerodynamic parameter settings include the chord length and sweep angle distributed along the blade span. The rotor blade structural parameter settings include the torsion angle, tensile stiffness, section moment of inertia, swing stiffness, flapping stiffness, torsional stiffness, linear mass distributed along the blade span, and also include the overall parameters of the rotor blade, such as the number of blades, rotation direction, tip speed, and hub type.

[0050] (3) Tail rotor modeling, including the setting of tail rotor blade airfoil parameters, tail rotor blade aerodynamic parameters and tail rotor blade structural parameters. The tail rotor blade airfoil parameter setting includes the aerodynamic data of each airfoil and the distribution of the airfoil along the blade span. The tail rotor blade aerodynamic parameter setting includes the chord length and sweep angle distributed along the blade span. The tail rotor blade structural parameter setting includes the torsion angle, tensile stiffness, section moment of inertia, swing stiffness, flapping stiffness, torsional stiffness, linear mass distributed along the blade span, and also includes the overall parameters of the tail rotor blade, such as the number of blades, rotation direction, tip speed, and hub type.

[0051] (4) Modeling of the horizontal tail, including the aerodynamic characteristics data of the horizontal tail, including the lift and drag of the horizontal tail that change with the angle of attack and the sideslip angle.

[0052] (5) Obtain more accurate rotor downwash velocity distribution at the tail rotor and horizontal tail. This can be calculated using computational fluid dynamics methods or obtained through experimental measurements. Figure 4 The downward velocity field distribution is calculated by the computational fluid dynamics method. The dotted circle area in the figure is the extracted velocity area. The velocity in the figure is dimensionless based on the rotor tip velocity in hovering. The dimensionless velocity extracted in the figure is 0.0333, and the corresponding true velocity is 0.0333×210m / s≈7m / s. The rotor downwash velocity in the front-to-back direction and the left-to-right direction can also be obtained accordingly.

[0053] (6) Embedding of fuselage flow field components. The purpose is to change the rotor downwash velocity distribution at the tail rotor and horizontal tail calculated by the software itself. The fuselage flow field component is embedded in the form of an interference velocity table file. The interference velocity given in the interference velocity table is centered on the center of the disturbed tail rotor hub and is distributed in azimuth and radial position in the plane of the actual position of the disturbed tail rotor. The interference velocity is in the fuselage coordinate system, and the positive direction of the interference velocity is defined as: X forward, Y right, and Z downward. The first dimension of the interference velocity table is the radial position, which is dimensionless and ranges from 0 to 1; the second dimension is the phase or time, and the phase unit is angle; the intermediate velocity units are Vx / V, Vy / V, and Vz / V; wherein Vx, Vy, and Vz represent the interference velocities in three directions, and V represents the flight speed of the entire aircraft. For this embodiment, the helicopter flight speed V is 21 m / s, and the downward velocity Vz of the rotor downwash is 7 m / s, so Vz / V≈0.333. The specific format is as follows: Figure 3 shown.

[0054] (7) The whole machine modeling is now completed.

[0055] (8) Carry out full aircraft trim calculation analysis based on specific flight conditions. The trim calculation settings mainly include trim targets, trim variables, trim calculation methods and convergence control.

[0056] In this embodiment, the trim target is the six force factors of the whole aircraft, and the trim variables are the rotor collective pitch, rotor longitudinal cyclic pitch, rotor lateral cyclic pitch, tail rotor collective pitch, horizontal tail rudder deflection angle and fuselage attitude angle.

[0057] According to the initial rotor collective pitch, rotor longitudinal cyclic pitch, rotor lateral cyclic pitch, combined with rotor blade airfoil parameters, rotor blade aerodynamic parameters, rotor blade structural parameters, tail rotor blade airfoil parameters, the aerodynamic force and torque of the rotor are calculated using blade element theory.

[0058] According to the initial tail rotor collective pitch, combined with the tail rotor blade airfoil parameters, tail rotor blade aerodynamic parameters, tail rotor blade structural parameters, the aerodynamic force and torque of the tail rotor are calculated using the blade element theory.

[0059] According to the initial horizontal tail rudder deflection angle and the horizontal tail aerodynamic characteristic data, the aerodynamic force and moment are obtained by interpolation calculation.

[0060] According to the initial fuselage attitude angle, fuselage aerodynamic characteristics data, overall parameters and rotor downwash velocity distribution, the aerodynamic force and moment of the fuselage are calculated using the lift line theory.

[0061] (9) By synthesizing the aerodynamic forces and moments of the rotor, tail rotor, horizontal stabilizer, and fuselage at the center of gravity of the fuselage, we can obtain the resultant force and moment acting on the center of gravity of the helicopter in the fuselage coordinate system. The equilibrium equations are as follows:

[0062] F X =F XMR +F XF +F XH +F XV +F XTR -mgsinΦ

[0063] F Y =F YMR +F YF +F YH +F YV +F YTR +mg

[0064] F Z =F ZMR +F ZF +F ZH +F ZV +F ZTR +mgcosΦ

[0065] M X =M XMR +M XF +M XH +M XTR

[0066] M Y =MYMR +M YF +M YH +M YTR

[0067] M Z =M ZMR +M ZF +M ZH +M ZTR

[0068] Among them, F represents force, M represents torque, m represents the weight of the fuselage, g represents the acceleration of gravity, and Φ represents the fuselage attitude angle.

[0069] Among them, the superscripts X, Y, and Z represent the three directions of the body coordinate system, the superscript MR represents the main rotor, the superscript F represents the fuselage, the superscript H represents the horizontal tail, and the superscript TR represents the tail rotor.

[0070] (10) Use Newton iteration method to solve the equilibrium equations and obtain the updated balancing variables. Check whether the obtained values ​​meet the convergence conditions corresponding to the balancing calculation tolerance. If they meet, the calculation ends; if not, replace the balancing variables in step (8) with the updated balancing variables and repeat steps (8), (9), and (10) until the convergence conditions are met.

[0071] (11) Output of calculation results of the example.

[0072] (12) Post-processing to obtain dynamic loads. A self-written small program is used to extract the time-varying aerodynamic loads on the tail rotor or horizontal tail from the complex calculation results, and the aerodynamic loads are further processed to calculate the tail rotor dynamic load or the horizontal tail dynamic load.

[0073] Figure 5 The comparison between the present invention and the test value is given. As can be seen from the figure, the present invention is in good agreement with the test value, indicating that the present invention can accurately estimate the dynamic load of helicopter components.

Claims

1. A component dynamic load estimation device taking into account rotor downwash interference, characterized in that: The components include a helicopter tail rotor and horizontal tail, and the device includes a full-machine module, and the full-machine module includes: The main rotor module is used to provide rotor blade airfoil parameters, rotor blade aerodynamic parameters and rotor blade structural parameters; A tail rotor module is used to provide tail rotor blade airfoil parameters, tail rotor blade aerodynamic parameters and tail rotor blade structural parameters; The horizontal tail module is used to provide the aerodynamic characteristics data of the horizontal tail; The fuselage module is used to provide fuselage aerodynamic characteristics data, overall parameters and rotor downwash velocity distribution; The trim analysis module is used to calculate the tail rotor dynamic load or the horizontal tail dynamic load.

2. The device according to claim 1, characterized in that The fuselage module comprises: The fuselage flow field assembly is used to provide rotor downwash velocity distribution.

3. The device according to claim 2, characterized in that The fuselage flow field component is embedded in the fuselage module in the form of an interference speed table file.

4. The device according to claim 1, characterized in that The trim analysis module is further used to call the rotor blade airfoil parameters, rotor blade aerodynamic parameters, rotor blade structural parameters, tail rotor blade airfoil parameters, tail rotor blade aerodynamic parameters, tail rotor blade structural parameters, horizontal tail aerodynamic characteristic data, fuselage aerodynamic characteristic data, overall parameters and rotor downwash velocity distribution; The trim analysis module is further used to adjust the rotor control amount, the tail rotor control amount, the horizontal tail rudder deflection angle and the fuselage attitude angle to perform six-force element trim of the entire aircraft based on the rotor blade airfoil parameters, the rotor blade aerodynamic parameters, the rotor blade structural parameters, the tail rotor blade airfoil parameters, the tail rotor blade aerodynamic parameters, the tail rotor blade structural parameters, the horizontal tail aerodynamic characteristic data, the fuselage aerodynamic characteristic data, the overall parameters and the rotor downwash velocity distribution, extract the aerodynamic load on the tail rotor or the horizontal tail that changes with time, further process the aerodynamic load, and calculate the tail rotor dynamic load or the horizontal tail dynamic load.

5. A method for estimating dynamic loads of helicopter components taking into account rotor downwash interference, characterized in that: The components include a helicopter tail rotor and a horizontal tail, and the method includes: The main rotor module provides rotor blade airfoil parameters, rotor blade aerodynamic parameters and rotor blade structural parameters; The tail rotor module provides tail rotor blade airfoil parameters, tail rotor blade aerodynamic parameters and tail rotor blade structural parameters; The horizontal tail module provides the horizontal tail aerodynamic characteristic data; The fuselage module provides fuselage aerodynamic characteristics data, overall parameters and rotor downwash velocity distribution; The trim analysis module receives the rotor blade airfoil parameters, rotor blade aerodynamic parameters, rotor blade structural parameters, tail rotor blade airfoil parameters, tail rotor blade aerodynamic parameters, tail rotor blade structural parameters, horizontal tail aerodynamic characteristic data, fuselage aerodynamic characteristic data, overall parameters and rotor downwash velocity distribution, and further calculates the tail rotor dynamic load or the horizontal tail dynamic load.

6. The method according to claim 5, characterized in that The fuselage module comprises a fuselage flow field component, and the fuselage flow field component is embedded in the fuselage module in the form of an interference speed table file.

7. The method according to claim 6, characterized in that The method further comprises: The fuselage flow field assembly provides the rotor downwash velocity distribution.

8. The method according to claim 1, characterized in that The method further comprises: The trim analysis module calls the rotor blade airfoil parameters, rotor blade aerodynamic parameters, rotor blade structural parameters, tail rotor blade airfoil parameters, tail rotor blade aerodynamic parameters, tail rotor blade structural parameters, horizontal tail aerodynamic characteristic data, fuselage aerodynamic characteristic data, overall parameters and rotor downwash velocity distribution; The trim analysis module adjusts the rotor control amount, the tail rotor control amount, the horizontal tail rudder deflection angle and the fuselage attitude angle to perform six-force element trim of the whole aircraft based on the rotor blade airfoil parameters, the rotor blade aerodynamic parameters, the rotor blade structural parameters, the tail rotor blade airfoil parameters, the tail rotor blade aerodynamic parameters, the tail rotor blade structural parameters, the horizontal tail aerodynamic characteristic data, the fuselage aerodynamic characteristic data, the overall parameters and the rotor downwash velocity distribution, extracts the aerodynamic load on the tail rotor or the horizontal tail that changes with time, further processes the aerodynamic load, and calculates the tail rotor dynamic load or the horizontal tail dynamic load.

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