A method for aerodynamic and mechanism integrated optimization design of three-dimensional high-lift device of an airplane

Abstract

The application discloses a kind of aeroplane three-dimensional lift-increasing device aerodynamic and mechanism integrated optimization design method, belong to aircraft technical field, comprising: parameterization modeling is carried out to aeroplane three-dimensional lift-increasing device;According to the value range of design variable defined according to parameterization modeling, a plurality of sample points are randomly generated, and an initial optimization population is formed;According to mechanism size and flap collision interference state, sample points are marked as feasible design or infeasible design;The take-off and landing performance of the sample point marked as feasible design is calculated;The initial optimization population is optimized using a multi-objective evolutionary algorithm, with the maximum lift coefficient of the take-off configuration at a given angle of attack and the maximum lift coefficient of the landing configuration at a given angle of attack as the optimization objectives, and the mechanism size and flap collision interference state as the constraint conditions, to find the optimal design variables iteratively. The application uses the above method to ensure the feasibility of the mechanism of the three-dimensional lift-increasing device while improving the take-off and landing performance of the aircraft.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft, and in particular to a method for optimizing the design of aerodynamic and structural integration of a three-dimensional high-lift device for an aircraft. Background Art

[0002] Since the 1980s, the aerodynamic shape and mechanism of high-lift devices have gradually evolved from complex to simple and reliable. The impact of multidisciplinary performance indicators such as structure, mechanism, and noise has been increasingly considered during aerodynamic optimization. The high-lift device mechanism supports and guides the flaps to the target takeoff and landing position. As the high-lift device type has become simpler, the focus of mechanism design has shifted from achieving complex positioning to reducing weight and maintenance costs, which has placed more constraints on aerodynamic optimization design. Currently, the most widely used high-lift device mechanisms include simple hinge mechanisms, four-bar linkages, and link-slide mechanisms.

[0003] Traditional aircraft lift-enhancing device design generally follows a process of two-dimensional design followed by three-dimensional simulation, and then aerodynamic optimization followed by mechanical design. The integrated aerodynamic and mechanical optimization design method for two-dimensional lift-enhancing devices can ensure the feasibility of mechanical design in two-dimensional multi-segment airfoils. However, for more complex mechanisms such as connecting rods and slides, the two-dimensional optimization design results cannot be directly applied to the aircraft's three-dimensional configuration, requiring the actual three-dimensional mechanical parameters to be recalculated. This may result in an inability to solve a feasible mechanism, leading to repeated iterations or even redesign. On the other hand, considering three-dimensional characteristics such as interference between aircraft components, spanwise twist angles, and variations in airfoil thickness and camber, there is no guarantee that a three-dimensional high-lift configuration generated based on the optimal two-dimensional multi-segment airfoil will achieve optimal three-dimensional aerodynamic performance.

[0004] Judging from the patents that have been published in China, the existing aerodynamic and structural integration optimization design methods of lift-enhancing devices are mainly aimed at two-dimensional multi-section airfoils, and there is a lack of methods for three-dimensional wings or wing-body combinations. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for optimizing the design of aerodynamic and mechanical integration of a three-dimensional high-lift device for an aircraft, so as to solve the problems mentioned in the above background.

[0006] To achieve the above-mentioned object, the present invention provides a method for optimizing the design of aerodynamic and mechanical integration of a three-dimensional high-lift device for an aircraft, the steps comprising:

[0007] S1. Parametrically modeling the multi-segment wing of a three-dimensional high-lift device of an aircraft, defining design variables, and obtaining an initial configuration of the high-lift device. The design variables include shape parameters and slot parameters.

[0008] S2. Randomly generate a number of sample points according to the value range of the design variables defined by the parametric modeling to form an initial optimization population;

[0009] S3. Calculate the three-dimensional spatial mechanism size and collision interference status of each sample point in the obtained optimization population. If the three-dimensional spatial mechanism size satisfies the constraints and no collision interference occurs during the flap deployment process, then mark the sample point as a feasible design; otherwise, mark the sample point as an infeasible design.

[0010] S4. Calculate the takeoff and landing performance of the sample points marked as feasible designs, including the lift coefficient of the takeoff configuration at a given angle of attack and the lift coefficient of the landing configuration at a given angle of attack;

[0011] S5. A multi-objective evolutionary algorithm is used to optimize the initial optimization population. The optimization objectives are to maximize the lift coefficient of the takeoff configuration at a given angle of attack and the lift coefficient of the landing configuration at a given angle of attack. The optimal design variables are iteratively searched for with the mechanism size and flap collision interference state as constraints.

[0012] Preferably, the parametric modeling method in step S1 is to use the quadratic curve method to generate a two-dimensional cross-sectional shape of the flap, obtain a three-dimensional flap shape based on the inner and outer flap sections, and then move the three-dimensional flap to the takeoff and landing positions required by the slot parameters through the translation and rotation of the rigid body to obtain the takeoff and landing configurations of the three-dimensional high-lift device, respectively.

[0013] Preferably, the three-dimensional space mechanism in step S3 is a connecting rod slide rail mechanism, and the design parameters of the connecting rod slide rail mechanism are the coordinates of the hinge connecting the crank and the connecting rod and the coordinates of the starting and ending positions of the slider on the slide rail.

[0014] Preferably, the three-dimensional space mechanism size and collision interference state of each sample point in the optimized population calculated in step S3 include: using the Newton-Raphson method to solve the mechanism design parameters of the sample point based on the geometric relationship of each rod of the three-dimensional space mechanism, judging whether the size of the mechanism meets the constraints based on the mechanism design parameters, and then calculating the flap trajectory based on the geometric relationship of each rod of the mechanism to determine the collision interference state.

[0015] Preferably, in step S3, the three-dimensional space mechanism size satisfies the constraint conditions and no collision interference occurs during the flap deployment process is defined as:

[0016] ;

[0017] Where, Indicates the distance from the slider to the leading edge of the wing during the movement of the three-dimensional space mechanism. It represents the distance from the slider to the wing plane during the movement of the three-dimensional space mechanism. is the crank angle, c is the local chord length of the wing, Indicates the collision interference status of the flaps.

[0018] Preferably, calculating the lift coefficient of the takeoff configuration at a given angle of attack and the lift coefficient of the landing configuration at a given angle of attack in step S4 includes: modifying the aircraft external flow field background grid and the flap boundary layer grid of the initial configuration according to the geometric model, using the overlapping grid method to generate calculation grids for the takeoff configuration and the landing configuration, respectively, and solving the lift coefficient of the takeoff configuration at a given angle of attack and the lift coefficient of the landing configuration at a given angle of attack based on the RANS equation and the kw-SST turbulence model.

[0019] Preferably, in the optimization process of step S5, the new sample point generated by the multi-objective optimization algorithm is judged: if the structure of the new sample point does not meet the constraint conditions, the new sample point is eliminated, its aerodynamic performance is not calculated, and the next new sample point is directly generated.

[0020] Therefore, the present invention adopts the above-mentioned aerodynamic and mechanical integrated optimization design method for a three-dimensional aircraft high-lift device, which has the following beneficial effects:

[0021] (1) The aerodynamic performance of the aircraft three-dimensional high-lift device in the present invention is designed and optimized synchronously with the three-dimensional spatial structure, thus avoiding repeated iterations of the design.

[0022] (2) Compared with the two-dimensional aerodynamic and structural integration optimization design method of the lift-enhancing device, this method is more direct and practical in constraining the feasibility of the three-dimensional spatial mechanism and has a better optimization effect on the aerodynamic performance.

[0023] (3) The solution of feasibility constraints of three-dimensional spatial mechanisms is relatively simple and only relies on the numerical solution of the equation group without calling simulation software.

[0024] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a flow chart of a method for optimizing the design of aerodynamic and mechanical integration of a three-dimensional high-lift device for aircraft according to the present invention;

[0026] Figure 2 A schematic diagram of a connecting rod and slide rail mechanism for an aircraft three-dimensional high-lift device according to the present invention;

[0027] Figure 3 This is a schematic diagram of the external parameters of the lift-enhancing device of the present invention;

[0028] Figure 4 This is a schematic diagram of the slot parameters of the lift-enhancing device of the present invention;

[0029] Figure 5 Schematic diagram of the overlapping grid used in the CFD calculation of the aerodynamic performance of the high-lift device of the present invention;

[0030] Reference numerals

[0031] 1, crank; 2, connecting rod; 3, slider; 4, slide rail; 5, rear beam. DETAILED DESCRIPTION

[0032] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present application.

[0033] EMBODIMENT

[0034] Fuller flap is a common aircraft trailing edge high-lift device, and its mechanism type mainly includes simple hinge mechanism, four-bar linkage mechanism and connecting rod slide rail mechanism. The profile and slot parameters of the flap and the design of the mechanism are the key to the design of the high-lift device.

[0035] WITH REFERENCE TO Figure 1 The present application provides a kind of aerodynamic and mechanism integrated optimization design method of aircraft three-dimensional high-lift device, and in the embodiment of the present application, single three-dimensional fuller flap and its connecting rod slide rail mechanism are selected for synchronous optimization design, and take-off performance and landing performance are optimization target, and the feasibility of mechanism (including mechanism size and collision interference state) is constraint condition.

[0036] The steps include:

[0037] S1, parameterized modeling is carried out on the multi-section wing of the aircraft three-dimensional high-lift device, design variables are defined, and the initial configuration of the high-lift device is obtained, and the design variables include profile parameters and slot parameters.

[0038] In the embodiment, the two-dimensional profile of the flap is generated using the quadratic curve method, the three-dimensional flap profile is obtained based on the inner and outer two flap profiles, and the three-dimensional flap is moved to the take-off and landing positions required by the slot parameters through the translation and rotation of the rigid body, respectively. The take-off and landing configurations of the three-dimensional high-lift device are obtained.

[0039] As Figure 3As shown in the figure, the flap's leading edge and upper surface are composed of three smooth, continuous quadratic curves: AB, BC, and CD. The rest of the flap conforms to the corresponding main wing shape. Parameter K controls the curvature of quadratic curve AB near the flap's leading edge, while parameter q controls the shape of quadratic curves AB and BC, i.e., the flap's upper surface shape. A, B, C, and D represent the flap's profile control points; K represents the flap's leading edge curvature control parameter; and q represents the flap's upper surface shape control parameter.

[0040] The start and end profiles of the flap along the span direction are controlled by two pairs of parameters K and q, which can take different values, thereby expanding the geometric shape design space of the three-dimensional flap. Figure 3 After the two flap sections along the span direction are drawn, the three-dimensional flap shape is generated using the guide line of the flap trailing edge. Then, the flaps are moved to the take-off and landing positions required by the slot parameters through the translation and rotation of the rigid body to obtain the aerodynamic shape of the three-dimensional proliferation device.

[0041] S2. According to the value range of the design variables defined by the parametric modeling, a number of sample points are randomly generated to form the initial optimization population.

[0042] In this embodiment, there are 6 design variables, namely K and q of the inner flap section, K and q of the outer flap section, and the slot parameter O of the takeoff configuration. f and G f , slot parameters O of landing configuration f and G f， Definition reference of design variables Figure 3 and Figure 4 , where O f Indicates flap overlap; G f Indicates the flap slot width; q f represents the flap deflection angle, and the number of initial optimized populations is 30.

[0043] S3. Calculate the three-dimensional spatial mechanism size and collision interference status of each sample point in the obtained optimization population. If the three-dimensional spatial mechanism size meets the constraints and no collision interference occurs during the flap deployment process, the sample point is marked as a feasible design; otherwise, the sample point is marked as an infeasible design.

[0044] In this embodiment, the three-dimensional spatial mechanism is a connecting rod slide rail mechanism, namely a spatial RSSP mechanism. The design parameters of the connecting rod slide rail mechanism are the coordinates of the hinge connecting the crank and the connecting rod and the coordinates of the starting and ending positions of the slider on the slide rail, such as Figure 2As shown in the figure, A1, B1, C1, and D1 represent the four points on the flap surface that are not coplanar when the Fuller flap is retracted; A2, B2, C2, and D2 represent the four points on the flap surface that are not coplanar when the Fuller flap is deployed to the take-off position. The spatial RSSP mechanism can be divided into a crank (RS) component and a slider (SP) component. According to the geometric relationship of the various rods of the mechanism, the hinge coordinates of these two components are solved separately. The cross-sectional position of the mechanism is located at 25% of the flap span. The process of deploying the flap from the retracted position to the take-off and landing position can be regarded as a three-position guidance problem of a rigid body, and the following rigid body displacement matrix is ​​obtained:

[0045] ;

[0046] ;

[0047] in, D 1to2 Represents the matrix of flaps extending from the stowed position to the takeoff position, D 1to3 Represents the flaps extended from the stowed position to the landing position matrix, and the subscripts 1, 2, and 3 represent the stowed, takeoff, and landing positions of the flaps, respectively.

[0048] Solve the RS component based on the fixed length and orthogonal conditions of the crank, assuming that point O is the intersection of the rotation plane of the crank spherical pair point P and the rotation axis u. Establish the RS component geometric equation:

[0049] ;

[0050] ;

[0051] ;

[0052] Where, O represents the hinge between the crank and the wing structure; P Represents the hinge between the crank and the connecting rod; Q Represents the hinge between the connecting rod and the slider;

[0053] Will ( i =2,3) into the above formula, we can get a set of 3 unknown vectors 、 、 and a system of 6 equations, with a total of 9 unknowns. Given the coordinates of point O, that is, the vector , the coordinates of point P and the direction of the rotation axis can be solved by the Newton-Raphson method.

[0054] Solve the SP component according to the linear motion condition of the spherical pair Q point on the slider. 、 、 The three points are collinear, and the subscripts 1, 2, and 3 represent the flap retraction, takeoff, and landing positions, respectively. Let k be an unknown constant and establish the linear guidance equation of the slider:

[0055] ;

[0056] Will Substituting these equations into the above formula yields a system of four unknowns and three equations. Given the z-coordinate of point Q (assuming it's located near the cross-section of the mechanism), the Newton-Raphson method is used to solve the problem. This method allows us to determine the mechanism parameters and trajectory for any given design variable, and thus determine whether the mechanism satisfies its constraints.

[0057] In this embodiment, the definition that the dimensions of the three-dimensional spatial mechanism satisfy the constraint conditions and that no collision interference occurs during the flap deployment process includes:

[0058] definition and are the distances from the slider to the leading edge of the wing and the wing plane during the movement of the mechanism, respectively. is the crank angle, and the upper and lower limits of these two values ​​define the size constraints of the mechanism. c is the local chord length of the wing. Logical variable Represents the collision interference state of the flap. The collision interference state refers to whether the flap collides with the fixed wing during the deployment process of the mechanism. Compared with the backward motion in the xy plane, the spanwise displacement of the flap during the deployment process is very small. Ignoring the small spanwise displacement of the flap, the mechanism can be projected onto the xy plane and the three-dimensional mechanism can be approximated as a two-dimensional mechanism, which is convenient for calculating the initial motion component of the point where the upper surface of the flap coincides with the trailing edge of the main wing when the crank rotates 1° If this component is positive, it means that the flap is tilted up too much while retreating, and the upper surface of the flap will collide with the trailing edge of the main wing. ;on the contrary, The constraints of an institution can be defined as:

[0059] .

[0060] S4. Calculate the takeoff and landing performance of the sample points marked as feasible designs, including the lift coefficient of the takeoff configuration at a given angle of attack and the lift coefficient of the landing configuration at a given angle of attack.

[0061] In this embodiment, the aircraft external flow field background grid and flap boundary layer grid of the initial configuration are modified according to the geometric model, and the computational grids of the takeoff configuration and landing configuration are generated respectively using the overlapping grid method. Based on the CFD algorithm, namely the RANS equation and the kw-SST turbulence model, the lift coefficient of the takeoff configuration at a given angle of attack and the lift coefficient of the landing configuration at a given angle of attack are solved. For an aircraft with a single Fuller flap, the overlapping grid is as shown in the attached figure. Figure 5As shown in the figure, the aircraft external flow field mesh is the background mesh, and the boundary layer mesh of the flap is the component mesh.

[0062] S5. A multi-objective evolutionary algorithm (NSGA-II) is used to optimize the initial optimization population. The optimization objectives are to maximize the lift coefficient of the takeoff configuration at a given angle of attack and the lift coefficient of the landing configuration at a given angle of attack. The optimal design variables are iteratively searched for, using the mechanism size and flap collision interference state as constraints. During the optimization process, new sample points generated by the multi-objective optimization algorithm are evaluated. If the mechanism of a new sample point does not meet the constraints, the new sample point is discarded, its aerodynamic performance is not calculated, and the next new sample point is generated directly.

[0063] In this embodiment, the optimal design variables are obtained by weighing the optimization targets obtained by the multi-objective optimization algorithm on the Pareto frontier according to different aircraft design requirements.

[0064] Therefore, the present invention adopts the above-mentioned integrated aerodynamic and structural optimization design method for a three-dimensional aircraft high-lift device. By simultaneously designing and optimizing the aerodynamic performance and three-dimensional spatial structure of the aircraft three-dimensional high-lift device, repeated design iterations are avoided. In addition, the three-dimensional design of the high-lift device makes the constraints on the feasibility of the structure more direct and practical, and the optimization effect on aerodynamic performance is better.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for optimizing the design of aerodynamic and mechanical integration of a three-dimensional high-lift device for an aircraft, characterized by the following steps: include: S1. Parametrically modeling the multi-segment wing of a three-dimensional high-lift device of an aircraft, defining design variables, and obtaining an initial configuration of the high-lift device. The design variables include shape parameters and slot parameters. The parametric modeling method uses the quadratic curve method to generate the two-dimensional cross-sectional shape of the flap, and then obtains the three-dimensional flap shape based on the inner and outer flap sections. Then, the three-dimensional flap is moved to the takeoff and landing positions required by the slot parameters through the translation and rotation of the rigid body, thereby obtaining the takeoff and landing configurations of the three-dimensional high-lift device respectively. S2. Randomly generate a number of sample points according to the value range of the design variables defined by the parametric modeling to form an initial optimization population; S3. Calculate the three-dimensional spatial mechanism size and collision interference status of each sample point in the obtained optimization population. If the three-dimensional spatial mechanism size satisfies the constraints and no collision interference occurs during the flap deployment process, then mark the sample point as a feasible design; otherwise, mark the sample point as an infeasible design. S4. Calculate the takeoff and landing performance of the sample points marked as feasible designs, including the lift coefficient of the takeoff configuration at a given angle of attack and the lift coefficient of the landing configuration at a given angle of attack; S5. A multi-objective evolutionary algorithm is used to optimize the initial optimization population. The optimization objectives are to maximize the lift coefficient of the takeoff configuration at a given angle of attack and the lift coefficient of the landing configuration at a given angle of attack. The optimal design variables are iteratively searched for with the mechanism size and flap collision interference state as constraints.

2. The method for integrated aerodynamic and mechanical optimization design of a three-dimensional aircraft high-lift device according to claim 1, characterized in that: In step S3 , the three-dimensional space mechanism is a connecting rod slide rail mechanism, and the design parameters of the connecting rod slide rail mechanism are the coordinates of the hinge connecting the crank and the connecting rod and the coordinates of the starting and ending positions of the slider on the slide rail.

3. The method for integrated aerodynamic and mechanical optimization design of a three-dimensional aircraft high-lift device according to claim 2, characterized in that: The three-dimensional space mechanism size and collision interference state of each sample point in the optimized population calculated in step S3 include: using the Newton-Raphson method to solve the mechanism design parameters of the sample point based on the geometric relationship of each rod of the three-dimensional space mechanism, judging whether the size of the mechanism meets the constraints based on the mechanism design parameters, and then calculating the flap trajectory based on the geometric relationship of each rod of the mechanism to determine the collision interference state.

4. The method for integrated aerodynamic and mechanical optimization design of a three-dimensional aircraft high-lift device according to claim 3, characterized in that: In step S3, the three-dimensional space mechanism size satisfies the constraint conditions and no collision interference occurs during the flap deployment process is defined as: ； Where, Indicates the distance from the slider to the leading edge of the wing during the movement of the three-dimensional space mechanism. Indicates the distance from the slider component to the wing plane during the movement of the three-dimensional space mechanism. is the crank angle, c is the local chord length of the wing, Indicates the collision interference status of the flaps.

5. The method for integrated aerodynamic and mechanical optimization design of a three-dimensional aircraft high-lift device according to claim 4, characterized in that: Calculating the lift coefficient of the takeoff configuration at a given angle of attack and the lift coefficient of the landing configuration at a given angle of attack in step S4 includes: modifying the aircraft external flow field background grid and the flap boundary layer grid of the initial configuration according to the geometric model, using the overlapping grid method to generate calculation grids for the takeoff configuration and the landing configuration, respectively, and solving the lift coefficient of the takeoff configuration at a given angle of attack and the lift coefficient of the landing configuration at a given angle of attack based on the RANS equation and the kω-SST turbulence model.

6. The method for integrated aerodynamic and mechanical optimization design of a three-dimensional aircraft high-lift device according to claim 5, characterized in that: In step S5, the new sample points generated by the multi-objective optimization algorithm are judged: if the structure of the new sample point does not meet the constraint conditions, the new sample point is eliminated, its aerodynamic performance is not calculated, and the next new sample point is directly generated.

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