KR20140140279A - System for the Aeroelastic Prediction of Rotor Craft Tail Unit and Controlling Method for the Same - Google Patents

Abstract

The present invention relates to a system for aeroelastic prediction for a tail unit of a rotorcraft, and a control method thereof. The control method comprises: a first step of allowing an analysis module to simulate the entire part of the rotorcraft including only a part of blades and to set and display an analysis model of the rotorcraft; a second step of allowing an analysis grid generation module to generate a grid to a predetermined size around the analysis model of the rotorcraft set by the analysis module and to display the generated grid, after the first step; a third step of allowing a calculation module to apply a turbulence calculation model to the analysis model around which the grid is generated by the analysis grid generation module, to input boundary conditions, and to perform an unsteady calculation, executing an unsteady analysis, after the second step; a fourth step of allowing a yawing moment extraction module to extract a yawing moment acting on the tail unit of the rotorcraft through a computing fluid analysis for the analysis model of the rotorcraft calculated and analyzed by the calculation module, and to display the extracted yawing moment, after the third step; and a fifth step of allowing an aeroelastic prediction module to perform FFT of the yawing moment data calculated by the yawing moment extraction module, analyze the size of vibration and a frequency, perform aeroelastic prediction for the tail unit of the rotorcraft, and output a prediction result. According to the present invention as described above, aircraft development costs and time may be reduced by predicting the size of vibration and performing the analysis of frequency quantitatively and precisely, wherein the vibration and frequency occur in a tail unit of a rotorcraft, through a computing fluid analysis.

Description

Technical Field [0001] The present invention relates to a system and a control method for a tail rotor vane vibration,

[0001] The present invention relates to a system for predicting a tactile aerodynamic vibration of a rotorcraft and a control method thereof, and more particularly, to a method for predicting a magnitude of a vibration caused by an aerodynamic interference caused by exposure of a rotorcraft aircraft tailwheel to a wake- And a control method thereof.

Generally, a helicopter is a type of helicopter, which is an aircraft that generates lift and propulsive force generated by turning a rotary wing, called a rotor blade, which generates lift, and is capable of vertical takeoff and landing and air stopping, So that forward, backward, and transverse movement can be performed. In addition, the design of the rotor blade provided in the rotor blade aircraft described above can be applied to a variety of designs in which the blade directly influences vibration characteristics, dynamic stability, and handling qualities as well as aerodynamic characteristics such as flight performance, aerodynamic load and noise A comprehensive review of the field is required. However, a tail shake phenomenon occurs in the rear portion of a conventional rotary wing aircraft. This tail shake phenomenon is a phenomenon that a vortex generated from a front hub such as a hub hub, an engine cowl, and a landing gear of a helicopter flows around a tail boom end structure, and is a vibration phenomenon caused by a typical aerodynamic interference caused by a helicopter . These vibrations can interfere with the pilot's mission. In addition, in the case of an armed helicopter such as one of the above-mentioned helicopter aircraft, the operation of the arming system may be affected and in the long term, fatigue failure of the equipment and the structure may be caused. However, the above-mentioned tail shake phenomenon is mostly found in the Flight Test stage of the prototype aircraft.

Referring to FIG. 1, the method for designing a conventional flywheel aircraft as described above includes a model specification setting process (S100) for setting a model specification of a helicopter as a flywheel aircraft;

A data input step (S200) of inputting design parameter values of the respective subsystems according to the model of the helicopter set after the model specification setting process (S100);

A linear modeling process (S300) for performing linear modeling that satisfies the helicopter steering specification ADS-33PRF after applying the requested model specification of the helicopter as a whole based on the data input after the data input process (S200) ;

(S400) for optimizing the control gain for the linear modeled development model after the linear modeling process (S300) and evaluating the performance through the flight test evaluation or the wind tunnel test and actually confirming the performance thereof .

Hereinafter, a method for designing a conventional helicopter aircraft will be described in more detail. A developer who develops a helicopter as a helicopter aircraft sets a model specification of a helicopter in a terminal (not shown) having a modeling program installed therein. After the model specification is set in the terminal as described above, the design parameter values of the respective subsystems according to the set helicopter model are inputted. Then, the modeling program built in the terminal performs the linear modeling satisfying the helicopter maneuvering standard ADS-33PRF after calculating the model specifications of the requested helicopter on the basis of the inputted data. Also, after optimizing the control gain for the linear modeled development model as described above, the performance is evaluated through the flight test or the wind tunnel test, and the tail shake phenomenon, which is usually generated at the tail portion of the rotor blade found in the performance evaluation, Reflect in the design of the aircraft.

However, in order to find a tail shake phenomenon, the conventional wind turbine design method is to perform a wind tunnel test using a normal flight test or a reduced model. Such a flight test or a wind tunnel test may be used as a model test or a test And it is difficult to realize the same flow condition and stiffness of the model as in the case of the wind tunnel. Therefore, it is very difficult to analyze the tailshake phenomenon precisely And thus the design stability of the rotor blade aircraft has been significantly reduced.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a method and apparatus for estimating the magnitude and frequency of vibration generated in a tail portion of a rotor- And to provide a control method for a tail rotor airstrip vibration prediction system that can reduce the rotation speed of a flywheel.

It is still another object of the present invention to provide a rotor blade aircraft capable of accurately estimating tail shake vibration characteristics by analyzing yaw moment acting on a vertical stabilizer plate or an electric body mounted on a tail portion of a rotor blade aircraft in real time, A vibration prediction system and a control method thereof.

According to an aspect of the present invention, there is provided an information processing apparatus comprising: an analysis module for modeling and displaying an analysis model of a rotor blade aircraft by simulating a whole portion of a rotor blade aircraft including only a part of blades;

An analysis grid generating module for generating and displaying a grid of a predetermined size around an analysis model of the rotor blade aircraft set by the analysis module;

A computation module for applying a turbulent computation model to an analytical model lattice-processed by the analytic grid generation module, inputting boundary conditions, and performing an unsteady computation to perform an unsteady analysis;

A yaw moment extraction module for extracting and displaying a yawing moment acting on an aircraft tail portion through a computational fluid analysis with respect to an analysis model of the flywheel aircraft calculated and analyzed by the calculation module;

And an aerodynamic vibration prediction module for performing an FFT process on the basis of the yaw moment data calculated by the yaw moment extraction module to predict the aerial vibration amplitude of the aircraft by analyzing the vibration amplitude of the frequency, do.

According to still another aspect of the present invention, there is provided a method for controlling an aircraft, the method comprising: a first step of setting and displaying an analysis model of a rotor blade aircraft by simulating an entire portion of a rotor blade aircraft including only a part of blades;

A second step of, after the first step, generating a grid of a predetermined size around the analysis model of the rotor blade aircraft set by the analysis module, by the analysis grid generation module;

A third step of, after the second step, applying a turbulent calculation model to the analytical model lattice-processed by the analytical grid generation module by the computation module, performing an unsteady computation after inputting the boundary conditions, ;

A fourth step of extracting and displaying a yawing moment acting on the aircraft tail through the computational fluid analysis with respect to the analysis model of the flywheel aircraft calculated and analyzed by the calculation module after the third process;

A fourth step of, after the fourth step, performing FFT processing on the yaw moment data calculated by the yaw moment extraction module by the aerodynamic vibration prediction module, and estimating and outputting the aerial antebellum aerodynamic vibration by analyzing the frequency, A method for controlling an aircraft aerodynamic vibration prediction system is provided.

According to the present invention, it is possible to quantitatively and precisely predict the magnitude and frequency of vibration generated in the tail portion of a rotorcraft aircraft through the computational fluid analysis, so that even if the flight test and the wind tunnel test are not performed, It accurately predicts the tail shake vibration and reflects it in the design of the rotor blade aircraft, thereby reducing the development cost and time of the aircraft.

As described above, It is possible to accurately estimate the tail shake vibration characteristics by analyzing the yawing moment acting on the vertical stabilizer plate or the electric body mounted on the tail of the rotor blade aircraft in real time, thereby reflecting the design of the rotor blade aircraft in the design of the rotor blade aircraft, thereby maximizing the stability of the rotor blade aircraft .

1 is an explanatory view for explaining an example of a conventional rotary-wing aircraft designing method;
BACKGROUND OF THE INVENTION Field of the Invention [0001]
3 is an explanatory view for explaining an example of an analysis module of a rotor blade aircraft according to the system of the present invention.
4 is an explanatory view for explaining a grid generation form of an analysis model set by the system of the present invention;
5 is a flowchart of the present invention.
Fig. 6 is an explanatory diagram comparing a wire type before and after mounting a common dome pairing. Fig.
7 is an explanatory view for explaining a velocity distribution of a Z-section in the vicinity of a general rotor hub;
8 is an explanatory view for explaining a comparison of FFT results of yaw moments acting on a vertical stabilizer according to presence or absence of dome pairing in the system of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a rotor propulsion ankle propulsion vibration prediction system according to the present invention will be described with reference to the accompanying drawings.

However, the present invention may be embodied in other forms without being limited to the embodiments of the rotor blade aircraft aerodynamic vibration prediction system according to the present invention described here. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals designate like elements throughout the specification. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. The term " comprises " And / or "comprising" does not exclude the presence or addition of one or more other elements, steps, operations, and / or elements.

Example

FIG. 2 is an explanatory view schematically explaining an embodiment of a tail rotor airstrip vibration prediction system according to the present invention, FIG. 3 is an explanatory view for explaining an example of an analysis module of a flywheel aircraft according to the system of the present invention, Fig. 5 is a flowchart of the present invention. Fig. 6 is an explanatory diagram comparing a wire type before and after mounting a common dome pairing. Fig. 7 is an explanatory view for explaining a velocity distribution of a Z section near a general rotor hub, and FIG. 8 is an explanatory view for explaining a comparison of FFT results for yaw moments acting on a vertical stabilizer according to whether dome pairing is performed in the system of the present invention.

Referring to FIG. 2, the system for predicting a tail rotor airstrip vibration according to an exemplary embodiment of the present invention includes an analysis module 1 for setting and displaying an analysis model 1 of a rotor fly aircraft by simulating a whole portion of a rotor fly aircraft including only some blades, (2);

An analysis grid generation module (3) for generating and displaying a grid of a predetermined size around the analysis model (1) of the rotor blade aircraft set by the analysis module (2);

A calculation module 4 for applying a turbulent calculation model to the analytical model 1 lattice-processed by the analytical grid generation module 3, inputting boundary conditions, performing an unsteady calculation, and;

A yaw moment extraction module 5 for extracting and displaying a yawing moment acting on an aircraft tail portion through a computational fluid analysis with respect to the analysis model 1 of the flywheel aircraft calculated and analyzed by the calculation module 4, ;

And an aerodynamic vibration prediction module 6 for FFT processing based on the yaw moment data calculated by the yaw moment extraction module 5 to analyze the vibration frequency and estimate the aerial vibration amplitude of the aircraft.

In order to set the analysis model of the rotor blade aircraft, the analysis module 2 simulates all parts of the rotor blade aircraft as shown in FIG. 3, without considering the tail rotor (hub and blade) (30% of the entire length of the blade), and the hub is simulated to be relatively similar to that of the hub. (When the blade is replicated within 30%, the vortices or wakes that occur at the tip become close to the vertical pin Which influences the overall analysis result), eliminating the blades in the analysis, which can save a considerable amount of computation time.

In order to perform a computational fluid dynamic analysis, the analysis grid generation module 3 generates a grid around the rotor-type aircraft model 1 as shown in FIG. 4, -10 times. At this time, the analysis grid generation module 3 constructs the external analysis region of the aircraft as a square, circle, or the like, and as the flow field changes around the fuselage, the closer to the fuselage the farther the fuselage is, Mainly, a lot of grids are concentrated in the space between the rotor hub and the engine cowl ~ vertical pin.

At this time, the calculation module 4 mainly performs the unsteady analysis when the turbo hub rotates at 272 rpm using the moving mesh method and examines the change in the backward flow due to the rotation of the main rotor. In this case, the time advance interval for the abnormal calculation is determined in consideration of the lattice size and the main hub rotation number, and the time advance calculation interval is preferably about 30 to 50 times.

On the other hand, the calculation module 4 can use a general k-e model for the turbulence model and a higher-order turbulence model that requires a longer calculation time. In addition, the calculation module (4) applies the boundary condition for the analysis, the forward velocity of the aircraft, the free-flow static pressure condition of the side and rear, and the wall boundary condition of the body.

Further, the calculation module 4 performs an unsteady analysis in order to analyze the yaw moment acting on the flywheel aircraft in real time. The time advance interval for the abnormal calculation considers the grid size and the main hub rotation number This normal time calculation interval is set to about 30 to 50, and the calculation is performed until the rotor hub rotates about eight times. At this time, unnecessary frequency components disappear in the vibration analysis as the number of revolutions increases, so that the accuracy of prediction can be increased.

On the other hand, the yaw moment extraction module 5 accurately extracts the forces and moments acting on the vertical stabilizer of the aircraft through the computational fluid analysis. The yaw moment extraction module 5 mainly extracts the forces acting on the vertical stabilizer The change in yaw moment is extracted.

Then, the aerodynamic vibration prediction module 6 performs FFT processing on yaw moment data of the extracted vertical stabilizer to analyze frequency and magnitude of vibration.

Next, a control method of the system of the present invention having the above-described configuration will be described.

The method of the present invention is characterized in that in the initial state (S1), as shown in Figure 5, the analysis module (2) simulates a whole part of a rotorcraft aircraft including only some blades and sets an analytical model (1) 1 step S2;

A second step S3 of generating and displaying a grid around the analysis model 1 of the rotor blade aircraft set by the analysis module 2 by the analysis grid generation module 3 after the first step S2, ;

After the second step S3, the calculation module 4 applies a turbulent calculation model to the analytical model 1 subjected to lattice processing by the analytical grid generation module 3, inputs boundary conditions, and then calculates an unsteady calculation (S4) for performing an abnormal analysis by performing the third step (S4);

After the third step S4, the yawing moment extraction module 5 calculates the yawing moment yawing moment acting on the aircraft tail through the computational fluid analysis for the analysis model 1 of the flywheel aircraft calculated and analyzed by the calculation module 4 a fourth step (S5) of extracting and displaying a moment;

After the fourth step S5, the aerodynamic vibration prediction module 6 performs FFT processing based on the yaw moment data calculated by the yaw moment extraction module 5 to analyze the vibration amplitude to estimate the aerial vibration of the aircraft And a fifth step (S6) of outputting the data.

Then, in the first step (S2), the analysis module simulates all the parts of the rotary-wing aircraft in order to set the analysis model of the rotary-wing aircraft, but does not simulate the tail rotor (hub and blades) (30% of the total length of the blade) to the root of the hub, but includes a concrete simulation step that simulates relatively realistic cases for the hub.

In the second step (S3), the analytical grid generation module forms a rectangular, circular, or similar shape in the external analysis area of the rotor blade airplane when the computational fluid dynamic analysis is performed. Since the flow field changes around the fuselage, And a lattice densification step for densifying the lattice more.

Further, in the third step (S4), the main module hub in which the calculation module rotates is simulated using a moving mesh technique, and a spherical analysis in which the change in the backward flow due to the main rotation is confirmed through an unsteady analysis .

In addition, in the third step (S4), the calculation module may use a general model (ke model) for the turbulence model or a higher-order turbulence model that requires calculation time, Further includes a condition setting step of applying the forward speed boundary condition of the aircraft, the free-flow static pressure condition of the side and rear direction, and the wall boundary condition of the fuselage.

Meanwhile, in the fourth step (S5), when the yaw moment extraction module extracts forces and moments acting on the vertical stabilizer of the aircraft through the computational fluid analysis, it acts mainly on the cumulative vertical stabilizer until the turbo hub rotates at least eight revolutions And an extraction condition setting step of extracting a change in yaw moment with time.

In other words, in order to utilize the flywheel avian aerodynamic vibration prediction system of the present invention, first, the analysis module 2 simulates the entire portion of the rotorcraft including only some blades to set the analysis model 1 of the rotorcraft aircraft, (7). The analysis grid generation module 3 generates a grid of a predetermined size around the analysis model 1 of the rotor blade aircraft set by the analysis module 2 and displays it on the system display 7. In addition, for the analytical model 1 which is lattice-processed by the analytical grid generation module 3 as described above, the calculation module 4 applies the turbulent model, inputs the boundary conditions, and performs an unsteady calculation Performs an abnormal analysis. The yawing moment extraction module 5 extracts a yawing moment acting on the aircraft tail portion through the computational fluid analysis with respect to the analysis model 1 of the rotary wing aircraft computationally analyzed through the above process, (7). Finally, based on the yaw moment data calculated through the above process, the aero-vibration prediction module 6 performs FFT processing to analyze the frequency of the vibration, and thus predicts the aircraft tentative aerodynamic vibration and outputs it to the system display 7 It is possible to quantitatively and precisely predict the amplitude and frequency analysis of the vibration generated in the tail portion of the rotor blade aircraft.

Hereinafter, the above process will be described in more detail. First, a method widely used for controlling the tail shake vibration is to mount a dome fairing on the rotor head. In the present invention, the present invention is applied to predicting the transverse vibration characteristics of the helicopter gas before and after mounting the dome-type pairing, and comparing the shapes of the wires passing around the dome pairing before and after mounting the dome pairing. At this time, the downward deflection effect of the flow due to the dome pairing is clearly shown as shown in FIG. In the absence of the dome pairing, it can be seen that the hub wake that occurs periodically as shown in FIG. 7 is generated. Such periodic wakes tend to be weakened or dispersed after mounting the dome pairing. 6 to 7, it can be confirmed that the lateral shaking is caused by unbalanced left and right pressures at the tail shake behind the center of gravity of the fuselage, especially around the vertical stabilizer at the end of the tail boom . This transverse vibration appears as a change in the yawing moment of the body. Therefore, since the tail shake vibration characteristic can be clearly understood by analyzing the yaw moment acting on the vertical stabilizer plate or the electric body in real time, the system 8 of the present invention performs FFT processing on the yaw moment in real time, It is possible to predict quantitatively and precisely the magnitude and frequency analysis of the vibration generated in the tail portion of the rotor blade aircraft by predicting the aircraft tail rotor vibration and outputting it on the system display 7. [

Here, the FFT results of the yaw moment acting on the vertical stabilizer according to the presence or absence of the dome pairing are compared as shown in FIG. In this case, when the dome pairing is not mounted, the vibration of the 2P, 3P, and 4P components appears. In the existing case, the tail shake vibration is closely related to the 1st lateral bending mode. In FIG. 8, it is expected that the 2P frequency component is a component that can cause tail shake vibration. These vibration components are extinguished or significantly reduced by the installation of the dome pairing. That is, it is considered that the dome pairing increases the voltage force by deflecting the flow at the center of the vertical axis, and the strong vortices generated from both sides of the dome pairing supply energy to the flow field to alleviate flow instability. Therefore, in the present invention system (8), it is possible to accurately predict the aerodynamic vibration of the tail portion of the rotor blade aircraft and to reflect the aerodynamic vibration in the design by analyzing these causes.

1: Analytical model 2: Analytical module
3: Analytical grid generation module 4: Calculation module
5: yaw moment extraction module 6: aerodynamic vibration prediction module
7: Aerodynamic Vibration Prediction Module 8: Aerodynamic Vibration Prediction System

Claims (8)

An analysis module for simulating a whole portion of a rotorcraft including only some blades and setting and displaying an analysis model of the rotorcraft;
An analysis grid generating module for generating and displaying a grid of a predetermined size around an analysis model of the rotor blade aircraft set by the analysis module;
A computation module for applying a turbulent computation model to an analytical model lattice-processed by the analytic grid generation module, inputting boundary conditions, and performing an unsteady computation to perform an unsteady analysis;
A yaw moment extraction module for extracting and displaying a yawing moment acting on an aircraft tail portion through a computational fluid analysis with respect to an analysis model of the flywheel aircraft calculated and analyzed by the calculation module;
And an aerodynamic vibration prediction module for predicting and outputting the aerial anthropogenic vibration of the aircraft by analyzing the vibration amplitude of the frequency by FFT processing based on the yaw moment data calculated by the yaw moment extraction module. The method according to claim 1,
Wherein the analysis grid generation module generates a grid around the rotor-fly aircraft model in the computational fluid dynamics analysis, and the analysis region considers at least 7-10 times the size of the fuselage. A first step of setting an analysis model of the rotor blade aircraft by displaying an entire part of the rotor blade aircraft including only a part of the blades, and displaying the analyzed model;
A second step of, after the first step, generating a grid of a predetermined size around the analysis model of the rotor blade aircraft set by the analysis module, by the analysis grid generation module;
A third step of, after the second step, applying a turbulent calculation model to the analytical model lattice-processed by the analytical grid generation module by the computation module, performing an unsteady computation after inputting the boundary conditions, ;
A fourth step of extracting and displaying a yawing moment acting on the aircraft tail through the computational fluid analysis with respect to the analysis model of the flywheel aircraft calculated and analyzed by the calculation module after the third process;
A fourth step of, after the fourth step, performing FFT processing on the yaw moment data calculated by the yaw moment extraction module by the aerodynamic vibration prediction module, and estimating and outputting the aerial antebellum aerodynamic vibration by analyzing the frequency, Control Method of Aircraft Aircraft Aerodynamic Vibration Prediction System. The method of claim 3,
In the first step, the analysis module simulates all parts of the rotorcraft aircraft in order to set up the rotorcraft analysis model, but does not simulate the tail rotor (hub and blade) but only the rotor (30% of the total length of the blade) of the hub, but in the case of the hub, it further includes a concrete simulation step that simulates a comparatively realistic simulation. The method of claim 3,
In the second step, the analytical grid generation module forms a rectangular, circular, or similar shape in the external analysis area of the rotor blade airplane when the computational fluid dynamic analysis is performed, and as the flow field changes around the fuselage, And a lattice densification step of densifying the lattice of the rotor blade. The method of claim 3,
The third step further includes a concrete analysis step of simulating a main hub on which the calculation module rotates using a moving mesh technique and confirming a change in the backward flow due to the rotation of the main body through an unsteady analysis (EN) The control method of a tail rotor airstream vibration prediction system characterized by a rotor blade. The method of claim 3,
In the third step, the calculation module is a boundary condition for the analysis of the turbulence model, and the condition setting step is to apply the forward speed boundary condition for the aircraft, the free flow constant pressure condition for the lateral direction and the rear direction, Further comprising the steps of: determining whether or not the at least one of the at least one of the at least two of the at least one of the at least two of the plurality of the at least one at least one of the plurality of the at least one non- The method of claim 3,
In the fourth step, when the yawing moment extraction module extracts the forces and moments acting on the vertical stabilizing plate of the aircraft through the computational fluid analysis, Further comprising an extraction condition setting step of extracting a change of a moment based on a result of the determination.

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