Aerodynamic configuration and design method of an accurate guidance assembly

Abstract

The application discloses a kind of aerodynamic configuration structures and design methods of precision guidance assembly, belong to the field of precision guidance technology, assembly precursor uses continuous three curve design: supersonic section, uses parabolic profile, surface is provided with rib, for optimizing shock control under supersonic working condition;Transonic section, uses hyperelliptic surface, surface is provided with rib and is pasted on rib with super material, for inhibiting transonic separation;Subsonic section: using circular arc transition, surface is provided with rib, for improving rudder surface lift efficiency;Wherein, curvature is continuous at three curve junctions.The application realizes supersonic-transonic-subsonic three-section coordinated design, simultaneously combines the coordinated drag reduction design of micro rib and super material technology, improves boundary layer from micro level, optimizes and improves the performance of guidance assembly.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of precision guidance technology, and particularly relates to a pneumatic shape structure and design method of a precision guidance assembly. BACKGROUND

[0002] The precision guidance assembly is a miniaturized assembly with satellite navigation, attitude sensing and correction rudder function, and can be applied to the fields of unmanned aerial vehicle observation, fire extinguishing (fire bomb head), artificial rainfall (rain bomb), etc. The pneumatic shape of the guidance assembly includes two schemes of single-segment and double-segment curve design. For the single-segment design, the front segment of the guidance assembly generally adopts a single-segment parabolic type or an approximately segmented reverse conical and parabolic splicing, which has limitations, such as in the Mach 1.2~1.5 interval, the shock wave is too concentrated, the intensity is large, and the wall separation is significant; meanwhile, no buffer zone is reserved for the transonic transition, which is easy to produce separation backflow, causing the stability to decrease. For the double-segment design, the double-segment parabolic top or composite conical design divides the front cone into two segments of different half angles of parabolic lines (such as segment 1 half angle 20°, segment 2 half angle 35°), in order to obtain smaller wave resistance in the supersonic speed segment, and meanwhile, to smoothly transition in the transonic to subsonic speed segment. However, the following defects exist:

[0003] a. Although the local shock wave intensity can be slightly reduced in a certain speed range, the speed changes rapidly in actual flight, and the aerodynamic center displacement is large;

[0004] b. In the transonic speed segment, the second segment parabolic line and the tail cone still have an angle, which often produces a secondary separation vortex;

[0005] c. The tail separation zone is not effectively translated or reduced without considering the tail convergence and rudder configuration.

[0006] The existing guidance assembly pneumatic shape generally adopts a two-segment design of "parabolic line + linear cylinder", but still has the following problems:

[0007] 1) Significant supersonic speed segment shock wave loss: the front end of the guidance assembly usually adopts a 20°~40° half cone angle parabolic line, and the curvature of the head assembly and the rear end assembly is discontinuous, which causes the secondary reflection of the shock wave to increase significantly.

[0008] 2) Transonic speed segment (0.8Ma~1.2Ma) separation peak problem: when the flight speed of the guidance assembly decreases to the interval of 0.8Ma~1.2Ma, the multi-layer shock wave generated by the front body and the rudder induced vortex are superimposed to form a complex shock wave boundary layer interference. The linear cylindrical tail segment adopted in the existing design cannot completely eliminate the separation zone without fully considering the flow field interference of the rudder layout, and faces a large resistance peak;

[0009] 3) Insufficient lift in subsonic speed segment: when the speed is less than 0.8Ma, the linear design of the tail of the existing guidance assembly does not consider the lift problem of the working area of the rudder.

[0010] The existing guidance assembly lacks overall optimized design for different states of supersonic shock, transonic separation and subsonic lift in the parabolic + linear cylindrical shape, resulting in performance still having room for improvement.

[0011] Therefore, it is difficult to meet the optimal aerodynamic requirements of each segment of supersonic, transonic and subsonic by single or double parabolic design.

[0012] Based on the above analysis, the existing guidance assembly has obvious short board in aerodynamic performance: the aerodynamic shape does not realize the coordinated design of supersonic, transonic and subsonic three segments. SUMMARY

[0013] The purpose of the present application is to overcome the problems existing in the prior art, and provide an aerodynamic shape structure and design method of precise guidance assembly.

[0014] The purpose of the present application is achieved by the following technical solutions:

[0015] In a first aspect, an aerodynamic shape structure of precise guidance assembly is provided, and the assembly forebody adopts continuous three-segment curve design:

[0016] The supersonic segment adopts parabolic profile, and the surface is provided with ribs for optimizing shock control under supersonic working condition;

[0017] The transonic segment adopts super-elliptical surface, and the surface is provided with ribs and coated with super material on the ribs for suppressing transonic separation;

[0018] The subsonic segment adopts circular arc transition, and the surface is provided with ribs for improving the lift efficiency of the rudder surface;

[0019] Wherein, the curvatures at the connection of the three-segment curves are continuous.

[0020] In some embodiments, the continuity of the curvatures at the connection of the three-segment curves satisfies the following formula, and the curvature change rate is less than 0.15:

[0021]

[0022] In the formula, represents the curvature at the connection of the supersonic segment and the transonic segment, represents the curvature at the connection of the transonic segment and the subsonic segment, and s is the arc length.

[0023] In some embodiments, the parabolic half-apex angle of the supersonic segment is 18°-22°.

[0024] In some embodiments, the transonic section rib is a V-shaped rib, the rib height is 100-180 μm, and the interval is 220-380 μm.

[0025] In some embodiments, the metamaterial is composed of a cavity array with a period of 200-300 μm, a cavity array diameter ≤100 μm, and a cavity array depth ≤100 μm.

[0026] In a second aspect, a design method of an aerodynamic configuration of a precision guidance assembly is provided, including the following steps:

[0027] S1. Establishing a three-section curve model of the assembly precursor, and defining the geometric parameters of the supersonic section, the transonic section and the subsonic section;

[0028] S2. Performing multidisciplinary coupling simulation based on the three-section curve model, and calculating performance indicators;

[0029] S3. Constructing a Kriging surrogate model to fit the nonlinear mapping relationship between the geometric parameters and the aerodynamic performance and the structural strength;

[0030] S4. Performing multi-objective optimization by using an NSGA-II algorithm, and outputting the optimal geometric parameter combination.

[0031] In some embodiments, the multidisciplinary coupling simulation based on the three-section curve model includes:

[0032] Joint computational fluid dynamics and finite element structure simulation, and realizing data interaction between the computational fluid dynamics and the finite element structure through a Python script.

[0033] In some embodiments, the multi-objective optimization by using the NSGA-II algorithm includes:

[0034] The objective function is to minimize the drag coefficient and the transonic separation index while satisfying the structural strength constraint; the transonic separation index is the ratio of the separation zone length to the assembly length.

[0035] It should be further explained that the technical features corresponding to the above embodiments can be combined or replaced with each other to form new technical solutions without conflict.

[0036] Compared with the prior art, the present application has the following advantages:

[0037] The present application realizes aerodynamic performance optimization through three-stage aerodynamic parameterization design (supersonic parabola, transonic hyper-ellipsoid and subsonic circular arc), and cooperatively reduces drag by combining micron-level ribs and super-material skin to improve the boundary layer from a micro perspective. Kriging proxy model and NSGA-II multi-objective optimization algorithm are used to optimize and improve the performance of the guidance assembly, significantly reducing the drag coefficient and separation zone index under the condition of meeting the structural strength constraint. The deficiencies of the existing guidance assembly in shock wave control, transonic separation and subsonic lift are solved, and the observation accuracy of the unmanned aerial vehicle and the dropping accuracy of the artificial rainfall bomb and fire extinguishing bomb are effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 Figure 1 is a schematic diagram of the aerodynamic shape structure of the present application precise guidance assembly;

[0039] Figure 2 Figure 2 is a design flowchart of the aerodynamic shape structure of the present application;

[0040] Figure 3 Figure 3 is a structural schematic diagram of the V-shaped rib of the present application;

[0041] Figure 4 Figure 4 is a Cp pressure coefficient distribution comparison diagram of a traditional guidance assembly and the shape of the present application under 1.5 Mach working condition;

[0042] Figure 5 Figure 5 is a drag coefficient comparison diagram of a traditional guidance assembly and the drag coefficient of the present application under 0 attack angle;

[0043] Figure 6 Figure 6 is a lift-drag ratio comparison of a traditional guidance assembly and the lift-drag ratio of the present application under 0 attack angle. DETAILED DESCRIPTION

[0044] The technical solutions of the present application will be described clearly and completely below in combination with the drawings. Obviously, the described embodiments are part 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 can be arranged and designed in various different configurations. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor should be within the scope of protection of the present application.

[0045] It should be noted that the defects in the above prior art solutions are the result of the inventors' practice and careful research, therefore, the discovery process of the above problems and the solutions proposed by the embodiments of the present application to the above problems should be the contribution of the inventors to the present application, and should not be understood as technical content known to those skilled in the art.

[0046] In an exemplary embodiment, asFigure 1 As shown, a three-section parameterized aerodynamic configuration structure of a precision guidance assembly is proposed, which effectively improves the precision of fire fighting and the launch accuracy of artificial rainfall shells, fully considers the axial length of the guidance assembly, the characteristics of the wave-transparent area and the rudder surface, adopts a three-section configuration strategy: the assembly forebody is divided into three sections of continuous curves, i.e., a supersonic section (section 1), a transonic section (section 2) and a subsonic section (section 3), each section adopts different geometric shapes (parabolic line, hyper-ellipsoid, circular arc), and the corresponding geometric functions are used for parameterized description to optimize the aerodynamic performance in the whole flight process.

[0047] Exemplarily, the structure of the present application is geometrically continuous and the Mach segment corresponds to:

[0048] Mach>1.2: parabolic forebody (θ1=18°~22°) delays shock wave generation, reduces wave drag coefficient, and optimizes shock wave control of the supersonic section of the assembly;

[0049] Mach0.8~1.2: hyper-ellipsoid surface (n=2.5) regulates the curvature change rate and suppresses separation;

[0050] Mach<0.8: circular arc transition (radius and length adjustable) matches the rudder surface lift requirement of the subsonic section and improves the rudder surface lift efficiency.

[0051] The structure considers shock wave control and transonic flow field regulation on the one hand, and coupling rib and metamaterial synergistic drag reduction design on the other hand. Specifically as follows:

[0052] 1. Shock wave control and transonic flow field regulation mechanism

[0053] 1) Supersonic section parabolic design theory

[0054] Shock wave control equation correlation: the parabolic half-apex angle θ1 and the shock wave angle β satisfy

[0055]

[0056] In the formula, β is the shock wave angle, θ1 is the parabolic half-apex angle, and M is the Mach number. When M=1.5 and θ1=20°, β=38.7° is calculated, which is significantly reduced compared with the traditional 45° shock wave angle of 30° half-apex angle.

[0057] Based on the Ackeret linearization theory, the wave drag coefficient is simplified as:

[0058]

[0059] In the formula, is the change amount of the wave drag coefficient, is the shock wave angle used in the present application, is the shock wave angle used in the traditional scheme.

[0060] This invention =18°~22° corresponds to the optimal shock wave angle for velocities of 1.3Ma~1.6Ma, which reduces the wave drag coefficient compared to the traditional 30° half-apex angle, with a theoretical reduction of 42%~58% calculated. Figure 4 The trend of change in the medium pressure coefficient is consistent.

[0061] 2) Transonic hyperellipsoid design mechanism

[0062] Curvature-controlled flow field mechanism:

[0063] Hyperellipsoid equation In the figure, the exponent n controls the fullness of the surface:

[0064] When n=2, it is a standard ellipsoid with a gentle curvature change, which is suitable for subsonic speeds.

[0065] When n=3, the surface is sharper, and the local curvature change rate reaches 2.3 times, which can adjust the position of the transonic shock wave.

[0066] Establish the length of the transonic separation region L sep Correlation with hyperellipsoid parameters:

[0067]

[0068] in, Indicates the major semi-axis. Indicates the short semi-axis. As the baseline length, the goodness of fit R 2 =0.92.

[0069] 3) Theory of Circular Transition in Subsonic Range

[0070] Curvature continuity condition:

[0071] Define the rate of change of curvature at the junction of the three curve segments. :

[0072]

[0073] In the formula: Let be the curvature of the second curve segment; Let be the curvature of the third curve segment.

[0074] Ensure that the pressure gradient change rate is less than 20% during airflow transition to avoid secondary separation. For the control surface layout of the components, the arc transition section can reduce the velocity gradient of the flow field near the control surface by 15%~20%, thereby improving lift efficiency.

[0075] 4) Refinement of the transonic transition mechanism

[0076] The three-segment curve connection meets the second derivative continuity, which is mathematically expressed as:

[0077]

[0078] In the formula represents the curvature of the connection between the supersonic section and the transonic section, represents the curvature of the connection between the transonic section and the subsonic section, and s is the arc length. Subsequently, through parameter optimization, the curvature variation rate of the connection is less than 5%, ensuring the flow field continuity of the component in the transonic section and avoiding separation caused by the sudden change of curvature at the connection between the component and the rear end of the component.

[0079] 2. Synergistic drag reduction design of ribs and metamaterials

[0080] Boundary layer turbulence suppression mechanism: V-shaped ribs (height H = 100-180 μm, spacing P = 220-380 μm) form ordered vortex structures in the boundary layer, decompose large-scale turbulence into micro-vortexes, reduce fluid kinetic energy dissipation, and reduce the friction drag coefficient by about 3-5%. The rib can effectively reduce the skin friction drag under Mach 1.5 conditions. It should be noted that not all rib surfaces have a drag reduction effect, and the rib parameters must meet certain conditions to have a drag reduction effect; otherwise, it will have a drag increasing effect.

[0081] Synergistic design with three-segment shape:

[0082] Supersonic section: Rib inhibits boundary layer transition, cooperates with parabolic precursor (θ1 = 18°-22°) to delay shock wave generation, reduces the peak value of wave drag and friction drag;

[0083] Transonic section: Rib weakens the shock wave-boundary layer interference near the hyper-elliptical surface, combined with the shock wave refraction effect of the metamaterial skin, shortens the separation zone length;

[0084] Subsonic section: Rib cooperates with circular arc transition to improve surface flow smoothness, enhances the lift efficiency of the control surface, and further improves the guidance performance.

[0085] Exemplarily, the rib and the shape shell are integrally formed through additive manufacturing. At the same time, the metamaterial skin (cavity array with a period of 200-300 μm) is attached to the key separation zone in the transonic section, forming a double drag reduction mechanism of "rib interference boundary layer + metamaterial shock wave control", which reduces the resistance more than a single means.

[0086] In this embodiment, the diameter of the metamaterial cavity array is ≤100 μm, and the depth is ≤100 μm, which realizes a 12%-15% increase in shock wave deflection angle in the transonic section without affecting the signal in the wave-transparent zone.

[0087] Based on the above structure, the application provides a corresponding design method, and the whole logic of the method is to establish a nonlinear mapping between three-section shape parameters (parabolic half vertex angle, hyperelliptical index, etc.), micro-rib parameters (height, spacing), and super material parameters (cavity period, diameter) and aerodynamic performance (drag coefficient C D , separation zone length L sep ), structural strength, after training by Latin hypercube design points, verify the model error, realize high-fidelity simulation and improve efficiency. Based on the Kriging model, NSGA~II algorithm is used for multi-objective optimization, taking min(C D ,S sep ) as the objective function, searching for the Pareto optimal solution set under the constraints of meeting the thermal working condition, launch overload, etc., driving the synergistic optimization of three-section shape (macro flow field regulation), micro-rib (boundary layer turbulence suppression), and super material (sub-wavelength shock wave regulation), forming a "macro-micro-sub-wavelength" cross-scale drag reduction mechanism, and finally realizing the purposes of reducing drag, improving lift-drag ratio, etc. The overall process is shown in Figure 2 .

[0088] The method realizes multi-objective coupling optimization: combining CFD (computational fluid dynamics) and FEM (finite element structure) simulation, performing integrated multi-objective optimization for flight performance (drag coefficient, separation vortex intensity) and structural strength (launch acceleration and thermal shock), obtaining the optimal geometric parameters of the guidance assembly, and realizing data interaction between CFD and FEM through Python script: CFD outputs pressure load to FEM for structural strength evaluation, and FEM outputs stress deformation to CFD to judge the influence of local shape change on aerodynamics (such as the maximum deformation of the shell under 10000g overload needs to be included in the aerodynamic simulation).

[0089] Based on the above structure and optimization design concept, the specific design process is described in detail as follows.

[0090] 1. Parameterized shape modeling

[0091] 1) Definition of precursor three-section curve

[0092] Section 1 (supersonic section): parabolic profile, parameterized as , wherein C1 is related to half cone vertex angle θ1, θ1∈[18°, 22°]; curve length L1∈[25mm, 35mm], accounting for 20%~25% of the total length of the assembly, to ensure shock wave control in the supersonic section.

[0093] Section 2 (transonic section): hyperelliptical surface, with parameter equation as

[0094]

[0095] Where the long semi-axis a ∈ [20 mm, 30 mm], the short semi-axis b ∈ [10 mm, 20 mm], and the curved surface index n ∈ [2.0, 3.0]. The curved surface length L2 is automatically determined by the above a, b, and n. If additional control is required, L2 ∈ [30 mm, 50 mm] can be allowed, which accounts for 30% to 40% of the component length, to regulate the transonic separation.

[0096] Section 3 (end smooth transition): circular arc section, transition circular arc radius R t ∈ [5 mm, 15 mm], transition length L t ∈ [10 mm, 20 mm]. The circular arc ensures smooth connection of the second curved surface, avoids local separation caused by sharp corners, and provides a smooth flow field for the rudder surface.

[0097] Design input parameter vector

[0098]

[0099] The initial values can be approximately determined based on conventional shapes and adjusted as needed (such as shortening the parabolic segment length to 30 mm and increasing the super-ellipsoid segment proportion), and then dynamically adjusted through simulation and optimization.

[0100] 2) Multidisciplinary coupling simulation

[0101] CFD simulation: ANSYS Fluent is used to perform fixed-point high-speed simulation at 1.2 Ma, 1.5 Ma, and 1.8 Ma, three key working conditions, with grid density ≥ 5 × 10 6 units, Spalart-Allmaras model or k-ω SST model is used to evaluate the shock position (e.g., shock angle β = 38.7° at M = 1.5), analyze pressure distribution, evaluate separation area size, and output pressure load data for the shape formed by the three curved lines.

[0102] FEM simulation: based on the three-dimensional model, Abaqus / ANSYS workbench is used to perform structural strength analysis of the shape under 30,000g launch load, with titanium alloy or 7075 aluminum alloy as the material, and the strain at key positions < 0.3%. At the same time, thermodynamic coupling is performed to simulate the transient thermal shock of the shell under the temperature (≈2000°C) inside the component, ensuring that the temperature gradient at the thinnest wall is < 200°C. Finally, FEM analysis performs: calculates structural stress; evaluates thermal shock; and outputs deformation and stress distribution data.

[0103] The coupling is realized by Python script. The pressure load output by CFD (e.g. 5 MPa maximum pressure at the head when M=1.8) is transmitted to FEM for strength evaluation. The stress distribution output by FEM (e.g. 700 MPa maximum stress at the joint) is fed back to CFD to judge the influence of local deformation on aerodynamics. If necessary, update the geometry (e.g. regenerate the mesh when the deformation is greater than 0.01 mm). After fusion, judge whether it meets the convergence condition. If not, update the geometry model and re-simulate.

[0104] 3) Construction of surrogate model

[0105] 200 design points are obtained by Latin hypercube sampling method. CFD / RANS simulation is run at three key speeds to obtain local drag coefficient C D ; separation zone index S sep (the ratio of separation zone length to component length).

[0106] Take P as input, and C D , S sep as output. Train the Kriging surrogate model with error <5% in the validation set. For the small-scale optimization space of the guidance component, the prediction accuracy of the surrogate model is improved. The aerodynamic performance can be quickly predicted during subsequent optimization iterations, effectively reducing the single calculation time.

[0107] 4) Multi-objective optimization

[0108] Objective function:

[0109]

[0110] Where: C D is the total drag coefficient; S sep is the transonic separation index (dimensionless value); f σ is the structural strength constraint; f tol is the robustness index; In this example, the weights α 1 =0.4, α 2 =0.3, α 3 =0.2, α 4 =0.1, reflect the balance between aerodynamic performance and engineering feasibility of the guidance component.

[0111] Combining NSGA-II and local gradient descent, NSGA-II is used to search the Pareto boundary in a large range at the initial stage, and the gradient descent is used to fine-tune the parameters for the local non-dominated solution set at the later stage. The optimization solution specific to the guidance assembly is obtained.

[0112] In this example, a plurality of groups of designs are obtained after optimization, one of which is at 1.5Ma operating conditions C D From 0.325 to 0.292; transonic separation index S sep From 0.14 to 0.08; the structural strength margin remains ≥1.2.

[0113] 2. Rib design and manufacture

[0114] 1) Rib layout and geometric design (note to avoid functional areas and rudder areas)

[0115] The optimal arrangement area is the transonic section (section 2): by using the smooth curvature characteristics of the curved surface, the rib interference transition boundary layer flow state is realized, which is far away from the wave-transparent area and does not affect signal transmission;

[0116] For geometric parameter optimization, according to the boundary layer thickness formula (δ≈0.37 x / Re 0.2 , x is the axial distance of the head, and Re is the Reynolds number), for example, the guidance assembly in this example is δ≈1.2mm at M=1.5 x =50mm, H=150μm (H / δ=0.125, in the optimal range 0.1~0.18 for drag reduction), P=300μm, to avoid secondary separation caused by excessive spacing;

[0117] For cross-sectional shape, V-shaped grooves (groove top radius r=5μm) are used in this example, as Figure 3 shown, the drag reduction effect is improved compared with rectangular ribs, and the vortex tube stability is better at high speed rotation.

[0118] 2) Metamaterial shock wave control design

[0119] In the transonic section, a metamaterial aerodynamic skin is attached, and the basic unit is a cavity array with a period of 250μm (diameter 80μm, depth 80μm), which satisfies d=250μm<λ / 2 (λ≈1.2mm when M=1.0), and realizes the shock wave deflection angle θ improvement. The cavity is filled with nitrogen gas (density 1.25kg / m³), and the equivalent refractive index is changed by adjusting the gas density, which dynamically optimizes the shock wave position in the range of M=0.9~1.1, and achieves the purpose of additional drag reduction compared with fixed structure.

[0120] 3) Microstructure parameter optimization

[0121] The geometric parameters of the ribs and the metamaterial are determined through a "boundary layer theory pre-design, multi-disciplinary simulation optimization, and proxy model acceleration" process.

[0122] A Kriging proxy model is used to fit a "structural parameter, drag reduction rate, and strength margin" mapping relationship, and the optimization target is to shorten the separation zone length by ≥20% in the transonic speed section and to improve the elevator surface lift efficiency by ≥20% in the subsonic speed section.

[0123] The design parameters need to meet the following requirements: not affecting the satellite navigation wave transmission performance; not damaging the shock wave control design in the supersonic speed section; and the structural strength safety factor ≥1.5 under high overload.

[0124] 4) Manufacturing degree control

[0125] The parameterized shape is realized through additive manufacturing, the titanium alloy powder layer thickness is 30 μm, the rib height precision is ±10 μm, and the metamaterial cavity array machining error is ≤±5 μm. In the manufacturing process, the laser selective melting (SLM) integrated forming is mainly used to avoid stress concentration in the traditional splicing process.

[0126] 3. Multi-disciplinary coupling optimization process

[0127] CFD simulation optimization rib parameters, in ANSYS Fluent, the rib surface boundary layer model is established, and the enhanced wall function is used to calculate the friction resistance coefficient of different H / P combinations. The preferred scheme is H=150 μm, P=300 μm, at this time C D 4.8% is reduced, and in the rotating working condition, the vortex tube shedding frequency is ≤200 Hz, avoiding resonance with the inherent frequency of the component body, and at the same time, the FEM strength is verified.

[0128] Proxy model acceleration optimization: a Kriging model is used to fit the "rib parameter, drag reduction rate, and structural strength" mapping relationship, in this example, the optimization iteration number is reduced from 200 times to 50 times, and the calculation efficiency is improved by 75%. A local enhanced sampling strategy is introduced, 20% sampling points are added near the Pareto boundary, and the accuracy of the optimization solution is improved.

[0129] Further, the simulation of the optimized shape is carried out in this embodiment, and the results are as follows:

[0130] Figure 4 The surface pressure coefficient variation trend of the traditional component and the three-stage shape of the application is compared. The shock wave of the application appears later, the peak pressure is lower, and the negative pressure area converges faster, which shows that it has better shock wave control and separation suppression ability. The improved shape of the application significantly reduces the drag coefficient C D (by about 10%) in the 1.2Ma-1.8Ma working condition, such as Figure 5The present application is superior to the conventional assembly in the whole flight Mach number interval, and the maximum improvement is up to 40%, as shown in the figure. Figure 6 The improvement of the lift-drag ratio means that the control efficiency in the guidance flight phase is higher and more stable, and the attack precision is improved.

[0131] The above specific embodiments are detailed descriptions of the present application, and cannot be considered as limitations of the specific embodiments of the present application. For those skilled in the art of the present application, without departing from the concept of the present application, a number of simple deductions and substitutions can be made, which should be considered as belonging to the protection scope of the present application.

Claims

1. An aerodynamic configuration of a precision guidance assembly, characterized by, The assembly precursor adopts a continuous three-segment curve design: The supersonic segment adopts a parabolic profile, and the surface is provided with ribs for optimizing shock control under supersonic working conditions; The transonic segment adopts a hyperelliptic surface, and the surface is provided with ribs and is coated with a metamaterial on the ribs for suppressing transonic separation; The subsonic segment adopts a circular arc transition, and the surface is provided with ribs for improving the lift efficiency of the control surface; The curvature at the connection of the three-segment curves is continuous, the curvature at the connection of the three-segment curves satisfies the following formula, and the curvature change rate is less than 0.15: where k1represents the curvature at the connection of the supersonic section with the transonic section, k2represents the curvature at the connection of the transonic section with the subsonic section, and s is the arc length.

2. The aerodynamic configuration of a precision guidance assembly according to claim 1, wherein, The parabolic half-apex angle of the supersonic segment is 18°-22°.

3. The aerodynamic configuration of a precision guidance assembly of claim 1, wherein, The transonic segment ribs are V-shaped ribs, the rib height is 100-180 μm, and the interval is 220-380 μm.

4. The aerodynamic configuration of a precision guidance assembly of claim 1, wherein, The metamaterial is composed of a cavity array with a period of 200-300 μm, the cavity array diameter is ≤100 μm, and the cavity array depth is ≤100 μm.

5. The method of designing the aerodynamic configuration of a precision guidance assembly according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: S1. Establishing a three-segment curve model of the assembly precursor, defining the geometric parameters of the supersonic segment, the transonic segment and the subsonic segment; S2. Multidisciplinary coupling simulation based on the three-segment curve model, and calculating performance indicators; S3. Constructing a Kriging surrogate model to fit the nonlinear mapping relationship between the geometric parameters and the aerodynamic performance and structural strength; S4. Multidisciplinary optimization using the NSGA-II algorithm to output the optimal geometric parameter combination.

6. The method of designing according to claim 5, wherein, The multidisciplinary coupling simulation based on the three-segment curve model comprises: Joint computational fluid dynamics and finite element structure simulation, and data interaction between the computational fluid dynamics and the finite element structure is realized through a Python script.

7. The method of designing according to claim 5, wherein, The multidisciplinary optimization using the NSGA-II algorithm comprises: The objective function is to minimize the drag coefficient and the transonic separation index while satisfying the structural strength constraint; the transonic separation index is the ratio of the separation zone length to the PGK assembly length.

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